diff --git a/orte/mca/db/daemon/db_daemon.c b/orte/mca/db/daemon/db_daemon.c
index 302da3b67a..60cc001d91 100644
--- a/orte/mca/db/daemon/db_daemon.c
+++ b/orte/mca/db/daemon/db_daemon.c
@@ -131,11 +131,11 @@ static int init(void)
         OBJ_CONSTRUCT(&datastore, opal_pointer_array_t);
         opal_pointer_array_init(&datastore, 16, INT_MAX, 16);
     } else if (ORTE_PROC_IS_APP) {
-        /* get my multicast group */
-        my_group_channel = orte_rmcast.query_channel();
+        /* get my multicast output group */
+        orte_rmcast.query_channel(&my_group_channel, NULL);
         
         /* recv responses */
-        if (ORTE_SUCCESS != (rc = orte_rmcast.recv_buffer_nb(ORTE_RMCAST_GROUP_CHANNEL,
+        if (ORTE_SUCCESS != (rc = orte_rmcast.recv_buffer_nb(my_group_channel,
                                                              ORTE_RMCAST_TAG_CMD_ACK,
                                                              ORTE_RMCAST_PERSISTENT,
                                                              recv_ack, NULL))) {
@@ -160,8 +160,7 @@ static int finalize(void)
         }
         OBJ_DESTRUCT(&datastore);
     } else if (ORTE_PROC_IS_APP) {
-        orte_rmcast.cancel_recv(ORTE_RMCAST_GROUP_CHANNEL, ORTE_RMCAST_TAG_DATA);
-        orte_rmcast.cancel_recv(ORTE_RMCAST_GROUP_CHANNEL, ORTE_RMCAST_TAG_CMD_ACK);
+        orte_rmcast.cancel_recv(my_group_channel, ORTE_RMCAST_TAG_WILDCARD);
     }
 
     return ORTE_SUCCESS;
diff --git a/orte/mca/rmcast/base/base.h b/orte/mca/rmcast/base/base.h
index 3d3dd7d50d..3fac9a9c63 100644
--- a/orte/mca/rmcast/base/base.h
+++ b/orte/mca/rmcast/base/base.h
@@ -53,7 +53,8 @@ typedef struct {
     bool active;
     opal_list_t recvs;
     opal_list_t channels;
-    rmcast_base_channel_t *my_group_channel;
+    rmcast_base_channel_t *my_output_channel;
+    rmcast_base_channel_t *my_input_channel;
 } orte_rmcast_base_t;
 
 ORTE_DECLSPEC extern orte_rmcast_base_t orte_rmcast_base;
diff --git a/orte/mca/rmcast/base/private.h b/orte/mca/rmcast/base/private.h
index 88ce000c45..283d8ca789 100644
--- a/orte/mca/rmcast/base/private.h
+++ b/orte/mca/rmcast/base/private.h
@@ -186,7 +186,8 @@ ORTE_DECLSPEC void orte_rmcast_base_cancel_recv(orte_rmcast_channel_t channel,
 
 ORTE_DECLSPEC int orte_rmcast_base_close_channel(orte_rmcast_channel_t channel);
 
-ORTE_DECLSPEC orte_rmcast_channel_t orte_rmcast_base_query(void);
+ORTE_DECLSPEC int orte_rmcast_base_query(orte_rmcast_channel_t *output,
+                                         orte_rmcast_channel_t *input);
 
 #endif /* ORTE_DISABLE_FULL_SUPPORT */
 
diff --git a/orte/mca/rmcast/base/rmcast_base_fns.c b/orte/mca/rmcast/base/rmcast_base_fns.c
index 65620efe80..d0bb6a31b5 100644
--- a/orte/mca/rmcast/base/rmcast_base_fns.c
+++ b/orte/mca/rmcast/base/rmcast_base_fns.c
@@ -60,7 +60,6 @@ int orte_rmcast_base_build_msg(rmcast_base_channel_t *ch,
         ORTE_ERROR_LOG(rc);
         return rc;
     }
-    
     /* are we sending a buffer? */
     if (NULL == snd->buf) {
         /* no, flag the buffer as containing iovecs */
@@ -69,7 +68,6 @@ int orte_rmcast_base_build_msg(rmcast_base_channel_t *ch,
             ORTE_ERROR_LOG(rc);
             goto cleanup;
         }
-        
         /* pack the number of iovecs */
         if (ORTE_SUCCESS != (rc = opal_dss.pack(buf, &snd->iovec_count, 1, OPAL_INT32))) {
             ORTE_ERROR_LOG(rc);
@@ -116,6 +114,7 @@ cleanup:
     if (NULL != buf) {
         OBJ_RELEASE(buf);
     }
+    *buffer = NULL;
     return rc;
 }
 
@@ -131,7 +130,7 @@ int orte_rmcast_base_queue_recv(rmcast_base_recv_t **recvptr,
     rmcast_base_recv_t *rptr;
     
     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                         "%s rmcast:tcp: queue_recv called on multicast channel %d tag %d",
+                         "%s rmcast:base: queue_recv called on multicast channel %d tag %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel, tag));
     
     if (!blocking) {
@@ -153,7 +152,7 @@ int orte_rmcast_base_queue_recv(rmcast_base_recv_t **recvptr,
                 if (NULL != rptr->cbfunc_iovec) {
                     /* already have one in place */
                     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                         "%s rmcast:tcp: matching recv already active on multicast channel %d tag %d",
+                                         "%s rmcast:base: matching recv already active on multicast channel %d tag %d",
                                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel, tag));
                     OPAL_THREAD_UNLOCK(&orte_rmcast_base.lock);
                     return ORTE_EXISTS;
@@ -164,7 +163,7 @@ int orte_rmcast_base_queue_recv(rmcast_base_recv_t **recvptr,
                 if (NULL != rptr->cbfunc_buffer) {
                     /* matching type - recv already in place */
                     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                         "%s rmcast:tcp: matching recv already active on multicast channel %d tag %d",
+                                         "%s rmcast:base: matching recv already active on multicast channel %d tag %d",
                                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel, tag));
                     OPAL_THREAD_UNLOCK(&orte_rmcast_base.lock);
                     return ORTE_EXISTS;
@@ -182,7 +181,7 @@ int orte_rmcast_base_queue_recv(rmcast_base_recv_t **recvptr,
     /* if we get here, then we need to add a new recv */
     
     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                         "%s rmcast:tcp: adding recv on multicast channel %d tag %d",
+                         "%s rmcast:base: adding recv on multicast channel %d tag %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel, tag));
     OPAL_THREAD_LOCK(&orte_rmcast_base.lock);
     rptr = OBJ_NEW(rmcast_base_recv_t);
@@ -252,7 +251,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
         goto cleanup;
     }
     
-    OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
+    OPAL_OUTPUT_VERBOSE((5, orte_rmcast_base.rmcast_output,
                          "%s rmcast:base:process_recv sender: %s channel: %d tag: %d %s seq_num: %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME),
                          ORTE_NAME_PRINT(&name), channel, (int)tag,
@@ -266,7 +265,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
         ptr = (rmcast_base_recv_t*)item;
         
         OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                             "%s rmcast:tcp:recv checking channel %d tag %d",
+                             "%s rmcast:base:recv checking channel %d tag %d",
                              ORTE_NAME_PRINT(ORTE_PROC_MY_NAME),
                              (int)ptr->channel, (int)ptr->tag));
         
@@ -279,7 +278,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
         }
         
         OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                             "%s rmcast:tcp:recv delivering message to channel %d tag %d",
+                             "%s rmcast:base:recv delivering message to channel %d tag %d",
                              ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), ptr->channel, (int)tag));
         
         /* we have a recv - unpack the data */
@@ -314,7 +313,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
             }
             if (NULL != ptr->cbfunc_iovec) {
                 OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                     "%s rmcast:tcp:recv delivering iovecs to channel %d tag %d",
+                                     "%s rmcast:base:recv delivering iovecs to channel %d tag %d",
                                      ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), ptr->channel, (int)tag));
                 
                 ptr->cbfunc_iovec(ORTE_SUCCESS, ptr->channel, tag,
@@ -330,7 +329,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
                 /* if something is already present, then we have a problem */
                 if (NULL != ptr->iovec_array) {
                     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                         "%s rmcast:tcp:recv blocking recv already fulfilled",
+                                         "%s rmcast:base:recv blocking recv already fulfilled",
                                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME)));
                     goto cleanup;
                 }
@@ -356,7 +355,7 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
             }                    
             if (NULL != ptr->cbfunc_buffer) {
                 OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                     "%s rmcast:tcp:recv delivering buffer to channel %d tag %d",
+                                     "%s rmcast:base:recv delivering buffer to channel %d tag %d",
                                      ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), ptr->channel, (int)tag));
                 
                 ptr->cbfunc_buffer(ORTE_SUCCESS, ptr->channel, tag,
@@ -372,12 +371,12 @@ void orte_rmcast_base_process_recv(orte_mcast_msg_event_t *msg)
                 /* if something is already present, then we have a problem */
                 if (NULL != ptr->buf) {
                     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                         "%s rmcast:tcp:recv blocking recv already fulfilled",
+                                         "%s rmcast:base:recv blocking recv already fulfilled",
                                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME)));
                     goto cleanup;
                 }
                 OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
-                                     "%s rmcast:tcp:recv copying buffer for blocking recv",
+                                     "%s rmcast:base:recv copying buffer for blocking recv",
                                      ORTE_NAME_PRINT(ORTE_PROC_MY_NAME)));
                 
                 /* copy the buffer across since it will be released
@@ -416,8 +415,10 @@ void orte_rmcast_base_cancel_recv(orte_rmcast_channel_t channel,
     rmcast_base_recv_t *ptr;
     orte_rmcast_channel_t ch;
     
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
         ch = orte_rmcast_base.my_group_number;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        ch = orte_rmcast_base.my_group_number + 1;
     } else {
         ch = channel;
     }    
@@ -462,9 +463,23 @@ int orte_rmcast_base_close_channel(orte_rmcast_channel_t channel)
     return ORTE_ERR_NOT_FOUND;
 }
 
-orte_rmcast_channel_t orte_rmcast_base_query(void)
+int orte_rmcast_base_query(orte_rmcast_channel_t *output, orte_rmcast_channel_t *input)
 {
-    return orte_rmcast_base.my_group_channel->channel;
+    if (NULL != output) {
+        if (NULL == orte_rmcast_base.my_output_channel) {
+            *output = ORTE_RMCAST_INVALID_CHANNEL;
+        } else {
+            *output =  orte_rmcast_base.my_output_channel->channel;
+        }
+    }
+    if (NULL != input) {
+        if (NULL == orte_rmcast_base.my_input_channel) {
+            *input = ORTE_RMCAST_INVALID_CHANNEL;
+        } else {
+            *input = orte_rmcast_base.my_input_channel->channel;
+        }
+    }
+    return ORTE_SUCCESS;
 }
 
 static int extract_hdr(opal_buffer_t *buf,
diff --git a/orte/mca/rmcast/base/rmcast_base_open.c b/orte/mca/rmcast/base/rmcast_base_open.c
index 2da6a8e1b3..073c9ae85c 100644
--- a/orte/mca/rmcast/base/rmcast_base_open.c
+++ b/orte/mca/rmcast/base/rmcast_base_open.c
@@ -117,7 +117,9 @@ int orte_rmcast_base_open(void)
     for (i=0; i < 255; i++) {
         orte_rmcast_base.ports[i] = 0;
     }
-    
+    orte_rmcast_base.my_output_channel = NULL;
+    orte_rmcast_base.my_input_channel = NULL;
+
     /* public multicast channel for this job */
     mca_base_param_reg_string_name("rmcast", "base_multicast_network",
                                 "Network to use for multicast xmissions [link (default) | site | org | global | tuple-addr]",
diff --git a/orte/mca/rmcast/rmcast.h b/orte/mca/rmcast/rmcast.h
index be246e6bf4..91aba3cce3 100644
--- a/orte/mca/rmcast/rmcast.h
+++ b/orte/mca/rmcast/rmcast.h
@@ -129,8 +129,9 @@ typedef int (*orte_rmcast_base_module_open_channel_fn_t)(orte_rmcast_channel_t c
 /* close the channel */
 typedef int (*orte_rmcast_base_module_close_channel_fn_t)(orte_rmcast_channel_t channel);
 
-/* return my group's channel */
-typedef orte_rmcast_channel_t (*orte_rmcast_base_module_query_channel_fn_t)(void);
+/* return my group's channels */
+typedef int (*orte_rmcast_base_module_query_channel_fn_t)(orte_rmcast_channel_t *output,
+                                                          orte_rmcast_channel_t *input);
 
 /*
  * rmcast component
diff --git a/orte/mca/rmcast/rmcast_types.h b/orte/mca/rmcast/rmcast_types.h
index d94510ba53..8c6bbdc6ff 100644
--- a/orte/mca/rmcast/rmcast_types.h
+++ b/orte/mca/rmcast/rmcast_types.h
@@ -26,7 +26,8 @@ typedef int32_t orte_rmcast_channel_t;
 #define ORTE_RMCAST_CHANNEL_T   OPAL_INT32
 
 /* ORTE IP multicast channels */
-#define ORTE_RMCAST_GROUP_CHANNEL          -2
+#define ORTE_RMCAST_GROUP_INPUT_CHANNEL    -3
+#define ORTE_RMCAST_GROUP_OUTPUT_CHANNEL   -2
 #define ORTE_RMCAST_WILDCARD_CHANNEL       -1
 #define ORTE_RMCAST_INVALID_CHANNEL         0
 #define ORTE_RMCAST_SYS_CHANNEL             1
diff --git a/orte/mca/rmcast/tcp/rmcast_tcp.c b/orte/mca/rmcast/tcp/rmcast_tcp.c
index 303a1a2229..e6098dc253 100644
--- a/orte/mca/rmcast/tcp/rmcast_tcp.c
+++ b/orte/mca/rmcast/tcp/rmcast_tcp.c
@@ -164,7 +164,8 @@ static int init(void)
             ORTE_ERROR_LOG(rc);
             return rc;
         }
-        orte_rmcast_base.my_group_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_output_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_input_channel = NULL;
     } else if (ORTE_PROC_IS_HNP || ORTE_PROC_IS_DAEMON) {
         /* daemons and hnp open the sys and data server channels */
         if (ORTE_SUCCESS != (rc = open_channel(ORTE_RMCAST_SYS_CHANNEL, "system",
@@ -172,7 +173,8 @@ static int init(void)
             ORTE_ERROR_LOG(rc);
             return rc;
         }
-        orte_rmcast_base.my_group_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_output_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_input_channel = NULL;
         if (ORTE_SUCCESS != (rc = open_channel(ORTE_RMCAST_DATA_SERVER_CHANNEL, "data-server",
                                                NULL, -1, NULL, ORTE_RMCAST_BIDIR))) {
             ORTE_ERROR_LOG(rc);
@@ -199,15 +201,22 @@ static int init(void)
             ORTE_ERROR_LOG(rc);
             return rc;
         }
-        /* finally, if we are an app, setup our grp channel, if one was given */
+        /* finally, if we are an app, setup our grp xmit/recv channels, if given */
         if (ORTE_PROC_IS_APP && NULL != orte_rmcast_base.my_group_name) {
             if (ORTE_SUCCESS != (rc = open_channel(orte_rmcast_base.my_group_number,
                                                    orte_rmcast_base.my_group_name,
-                                                   NULL, -1, NULL, ORTE_RMCAST_BIDIR))) {
+                                                   NULL, -1, NULL, ORTE_RMCAST_RECV))) {
                 ORTE_ERROR_LOG(rc);
                 return rc;
             }
-            orte_rmcast_base.my_group_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+            orte_rmcast_base.my_input_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+            if (ORTE_SUCCESS != (rc = open_channel(orte_rmcast_base.my_group_number+1,
+                                                   orte_rmcast_base.my_group_name,
+                                                   NULL, -1, NULL, ORTE_RMCAST_XMIT))) {
+                ORTE_ERROR_LOG(rc);
+                return rc;
+            }
+            orte_rmcast_base.my_output_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
         }
     } else {
         opal_output(0, "rmcast:tcp:init - unknown process type");
@@ -292,12 +301,12 @@ static int queue_xmit(rmcast_base_send_t *snd,
     /* if we were asked to send this on our group output
      * channel, substitute it
      */
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        if (NULL == orte_rmcast_base.my_group_channel) {
+    if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        if (NULL == orte_rmcast_base.my_output_channel) {
             ORTE_ERROR_LOG(ORTE_ERR_NOT_FOUND);
             return ORTE_ERR_NOT_FOUND;
         }
-        ch = orte_rmcast_base.my_group_channel;
+        ch = orte_rmcast_base.my_output_channel;
         goto process;
     }
     
@@ -518,8 +527,10 @@ static int tcp_recv(orte_process_name_t *name,
     int ret;
     orte_rmcast_channel_t chan;
 
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -563,8 +574,10 @@ static int tcp_recv_nb(orte_rmcast_channel_t channel,
                          "%s rmcast:tcp: recv_nb called on channel %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel));
     
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -594,8 +607,10 @@ static int tcp_recv_buffer(orte_process_name_t *name,
                          "%s rmcast:tcp: recv_buffer called on multicast channel %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel));
 
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -641,8 +656,10 @@ static int tcp_recv_buffer_nb(orte_rmcast_channel_t channel,
                          "%s rmcast:tcp: recv_buffer_nb called on multicast channel %d tag %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel, tag));
     
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
diff --git a/orte/mca/rmcast/udp/rmcast_udp.c b/orte/mca/rmcast/udp/rmcast_udp.c
index c6765a80d8..4e9047a6c0 100644
--- a/orte/mca/rmcast/udp/rmcast_udp.c
+++ b/orte/mca/rmcast/udp/rmcast_udp.c
@@ -48,7 +48,7 @@ static int setup_channel(rmcast_base_channel_t *chan, uint8_t direction);
 
 static int setup_socket(int *sd, rmcast_base_channel_t *chan, bool recvsocket);
 
-static void xmit_data(int sd, short flags, void* send_req);
+static int xmit_data(rmcast_base_channel_t *chan, rmcast_base_send_t *snd);
 
 /* API FUNCTIONS */
 static int init(void);
@@ -161,7 +161,8 @@ static int init(void)
             ORTE_ERROR_LOG(rc);
             return rc;
         }
-        orte_rmcast_base.my_group_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_output_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_input_channel = NULL;
     } else if (ORTE_PROC_IS_HNP || ORTE_PROC_IS_DAEMON) {
         /* daemons and hnp open the sys and data server channels */
         if (ORTE_SUCCESS != (rc = open_channel(ORTE_RMCAST_SYS_CHANNEL, "system",
@@ -169,12 +170,13 @@ static int init(void)
             ORTE_ERROR_LOG(rc);
             return rc;
         }        
+        orte_rmcast_base.my_output_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+        orte_rmcast_base.my_input_channel = NULL;
         if (ORTE_SUCCESS != (rc = open_channel(ORTE_RMCAST_DATA_SERVER_CHANNEL, "data-server",
                                                NULL, -1, NULL, ORTE_RMCAST_BIDIR))) {
             ORTE_ERROR_LOG(rc);
             return rc;
         }
-        orte_rmcast_base.my_group_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
     } else if (ORTE_PROC_IS_APP) {
         /* apps open the app public and data server channels */
         if (ORTE_SUCCESS != (rc = open_channel(ORTE_RMCAST_APP_PUBLIC_CHANNEL, "app-announce",
@@ -187,15 +189,22 @@ static int init(void)
             ORTE_ERROR_LOG(rc);
             return rc;
         }
-        /* also setup our grp channel, if one was given */
-        if (NULL != orte_rmcast_base.my_group_name) {
+         /* finally, if we are an app, setup our grp xmit/recv channels, if given */
+        if (ORTE_PROC_IS_APP && NULL != orte_rmcast_base.my_group_name) {
             if (ORTE_SUCCESS != (rc = open_channel(orte_rmcast_base.my_group_number,
                                                    orte_rmcast_base.my_group_name,
-                                                   NULL, -1, NULL, ORTE_RMCAST_BIDIR))) {
+                                                   NULL, -1, NULL, ORTE_RMCAST_RECV))) {
                 ORTE_ERROR_LOG(rc);
                 return rc;
             }
-            orte_rmcast_base.my_group_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+            orte_rmcast_base.my_input_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
+            if (ORTE_SUCCESS != (rc = open_channel(orte_rmcast_base.my_group_number+1,
+                                                   orte_rmcast_base.my_group_name,
+                                                   NULL, -1, NULL, ORTE_RMCAST_XMIT))) {
+                ORTE_ERROR_LOG(rc);
+                return rc;
+            }
+            orte_rmcast_base.my_output_channel = (rmcast_base_channel_t*)opal_list_get_last(&orte_rmcast_base.channels);
         }
     } else {
         opal_output(0, "rmcast:udp:init - unknown process type");
@@ -253,12 +262,12 @@ static int queue_xmit(rmcast_base_send_t *snd,
     /* if we were asked to send this on our group output
      * channel, substitute it
      */
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        if (NULL == orte_rmcast_base.my_group_channel) {
+    if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        if (NULL == orte_rmcast_base.my_output_channel) {
             ORTE_ERROR_LOG(ORTE_ERR_NOT_FOUND);
             return ORTE_ERR_NOT_FOUND;
         }
-        ch = orte_rmcast_base.my_group_channel;
+        ch = orte_rmcast_base.my_output_channel;
         goto process;
     }
     
@@ -288,18 +297,7 @@ process:
                          (NULL == snd->iovec_array) ? "bytes" : "iovecs",
                          OPAL_IF_FORMAT_ADDR(ch->network)));
     
-    /* add it to this channel's pending sends */
-    OPAL_THREAD_LOCK(&ch->send_lock);
-    opal_list_append(&ch->pending_sends, &snd->item);
-    
-    /* do we need to start the send event? */
-    if (!ch->sends_in_progress) {
-        opal_event_add(&ch->send_ev, 0);
-        ch->sends_in_progress = true;
-    }
-    OPAL_THREAD_UNLOCK(&ch->send_lock);
-    
-    return ORTE_SUCCESS;
+    return xmit_data(ch, snd);
 }
 
 static int udp_send(orte_rmcast_channel_t channel,
@@ -413,8 +411,10 @@ static int udp_recv(orte_process_name_t *name,
     int ret;
     orte_rmcast_channel_t chan;
 
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -458,8 +458,10 @@ static int udp_recv_nb(orte_rmcast_channel_t channel,
                          "%s rmcast:udp: recv_nb called on channel %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel));
     
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -488,8 +490,10 @@ static int udp_recv_buffer(orte_process_name_t *name,
                          "%s rmcast:udp: recv_buffer called on multicast channel %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel));
 
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -535,8 +539,10 @@ static int udp_recv_buffer_nb(orte_rmcast_channel_t channel,
                          "%s rmcast:udp: recv_buffer_nb called on multicast channel %d tag %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), channel, tag));
     
-    if (ORTE_RMCAST_GROUP_CHANNEL == channel) {
-        chan = orte_rmcast_base.my_group_number;
+    if (ORTE_RMCAST_GROUP_INPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_input_channel->channel;
+    } else if (ORTE_RMCAST_GROUP_OUTPUT_CHANNEL == channel) {
+        chan = orte_rmcast_base.my_output_channel->channel;
     } else {
         chan = channel;
     }
@@ -740,8 +746,6 @@ static int setup_channel(rmcast_base_channel_t *chan, uint8_t direction)
         }
         chan->xmit = xmitsd;
         chan->send_data = (uint8_t*)malloc(orte_rmcast_udp_sndbuf_size);
-        /* setup the event to xmit messages, but don't activate it */
-        opal_event_set(&chan->send_ev, chan->xmit, OPAL_EV_WRITE, xmit_data, chan);        
     }
     
     if (0 > chan->recv && ORTE_RMCAST_RECV & direction) {
@@ -903,31 +907,24 @@ static int setup_socket(int *sd, rmcast_base_channel_t *chan, bool recvsocket)
     return ORTE_SUCCESS;
 }
 
-static void xmit_data(int sd, short flags, void* send_req)
+static int xmit_data(rmcast_base_channel_t *chan, rmcast_base_send_t *snd)
 {
-    rmcast_base_channel_t *chan = (rmcast_base_channel_t*)send_req;
-    rmcast_base_send_t *snd;
-    opal_list_item_t *item;
     char *bytes;
     int32_t sz;
     int rc;
     opal_buffer_t *buf;
-    rmcast_send_log_t *log, *lg;
     
-    OPAL_THREAD_LOCK(&chan->send_lock);
     OPAL_OUTPUT_VERBOSE((2, orte_rmcast_base.rmcast_output,
                          "%s transmitting data for channel %d",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), chan->channel));
-    
-    while (NULL != (item = opal_list_remove_first(&chan->pending_sends))) {
-        snd = (rmcast_base_send_t*)item;
-        
+
         /* setup the message for xmission */
         if (ORTE_SUCCESS != (rc = orte_rmcast_base_build_msg(chan, &buf, snd))) {
             ORTE_ERROR_LOG(rc);
             goto CLEANUP;
         }
         
+#if 0
         /* store the working buf in the send ring buffer in case we
          * need to retransmit it later
          */
@@ -943,7 +940,8 @@ static void xmit_data(int sd, short flags, void* send_req)
                                  lg->seq_num, lg->channel));
             OBJ_RELEASE(lg);
         }
-        
+#endif
+
         /* unload the working buf to obtain the payload */
         if (ORTE_SUCCESS != (rc = opal_dss.unload(buf, (void**)&bytes, &sz))) {
             ORTE_ERROR_LOG(rc);
@@ -965,6 +963,8 @@ static void xmit_data(int sd, short flags, void* send_req)
                         ORTE_NAME_PRINT(ORTE_PROC_MY_NAME), OPAL_IF_FORMAT_ADDR(chan->network),
                         strerror(errno), errno);
             rc = errno;
+        } else {
+            rc = ORTE_SUCCESS;
         }
         
         if (NULL != snd->buf) {
@@ -983,14 +983,6 @@ static void xmit_data(int sd, short flags, void* send_req)
 
         /* roll to next message sequence number */
         ORTE_MULTICAST_NEXT_SEQUENCE_NUM(chan->seq_num);
-CLEANUP:        
-        /* cleanup */
-        OBJ_RELEASE(item);
-    }
-    
-    /* cleanup */
-    opal_event_del(&chan->send_ev);
-    chan->sends_in_progress = false;
-
-    OPAL_THREAD_UNLOCK(&chan->send_lock);
+CLEANUP:
+        return rc;    
 }
diff --git a/orte/test/system/orte_mcast.c b/orte/test/system/orte_mcast.c
index 7c8ad4bdce..42f6838579 100644
--- a/orte/test/system/orte_mcast.c
+++ b/orte/test/system/orte_mcast.c
@@ -41,20 +41,22 @@ static int datasize=1024;
 static void send_data(int fd, short flags, void *arg)
 {
     opal_buffer_t buf, *bfptr;
-    int32_t i32;
+    int32_t *i32;
     struct iovec iovec_array[3];
     int rc, i;
     opal_event_t *tmp = (opal_event_t*)arg;
     struct timeval now;
 
     bfptr = OBJ_NEW(opal_buffer_t);
-    i32 = -1;
-    opal_dss.pack(bfptr, &i32, datasize, OPAL_INT32);
-    if (ORTE_SUCCESS != (rc = orte_rmcast.send_buffer_nb(ORTE_RMCAST_GROUP_CHANNEL,
+    i32 = (int32_t*)malloc(datasize*sizeof(int32_t));
+    for (i=0; i < datasize; i++) {
+        i32[i] = -1;
+    }
+    opal_dss.pack(bfptr, i32, datasize, OPAL_INT32);
+    if (ORTE_SUCCESS != (rc = orte_rmcast.send_buffer_nb(ORTE_RMCAST_GROUP_OUTPUT_CHANNEL,
                                                          ORTE_RMCAST_TAG_OUTPUT, bfptr,
                                                          cbfunc_buf_snt, NULL))) {
         ORTE_ERROR_LOG(rc);
-        OBJ_RELEASE(bfptr);
         return;
     }        
     /* create an iovec array */
@@ -63,7 +65,7 @@ static void send_data(int fd, short flags, void *arg)
         iovec_array[i].iov_len = datasize;
     }
     /* send it out */
-    if (ORTE_SUCCESS != (rc = orte_rmcast.send(ORTE_RMCAST_GROUP_CHANNEL,
+    if (ORTE_SUCCESS != (rc = orte_rmcast.send(ORTE_RMCAST_GROUP_OUTPUT_CHANNEL,
                                                ORTE_RMCAST_TAG_OUTPUT,
                                                iovec_array, 3))) {
         ORTE_ERROR_LOG(rc);
@@ -108,13 +110,13 @@ int main(int argc, char* argv[])
         ORTE_TIMER_EVENT(5, 0, send_data);
     } else {
         /* setup to recv data on our channel */
-        if (ORTE_SUCCESS != (rc = orte_rmcast.recv_buffer_nb(ORTE_RMCAST_GROUP_CHANNEL,
+        if (ORTE_SUCCESS != (rc = orte_rmcast.recv_buffer_nb(ORTE_RMCAST_GROUP_OUTPUT_CHANNEL,
                                                              ORTE_RMCAST_TAG_OUTPUT,
                                                              ORTE_RMCAST_PERSISTENT,
                                                              cbfunc, NULL))) {
             ORTE_ERROR_LOG(rc);
         }
-        if (ORTE_SUCCESS != (rc = orte_rmcast.recv_nb(ORTE_RMCAST_GROUP_CHANNEL,
+        if (ORTE_SUCCESS != (rc = orte_rmcast.recv_nb(ORTE_RMCAST_GROUP_OUTPUT_CHANNEL,
                                                       ORTE_RMCAST_TAG_OUTPUT,
                                                       ORTE_RMCAST_PERSISTENT,
                                                       cbfunc_iovec, NULL))) {