Ask and 70.93 seconds later you shall receive - cross server message channel.

proxy/src/main/java/net/md_5/bungee/UserConnection.java

@@ -481,6 +481,14 @@ public class UserConnection extends GenericConnection implements ProxiedPlayer
 
                                     getServer().sendData("BungeeCord", b.toByteArray());
                                 }
+                                if (subChannel.equals("Message"))
+                                {
+                                    ProxiedPlayer target = ProxyServer.getInstance().getPlayer(in.readUTF());
+                                    if (target != null)
+                                    {
+                                        target.sendMessage(in.readUTF());
+                                    }
+                                }
                                 continue;
                             }
                     }