can't receive any Netgroup event

Here is the code. After user connects to the group, I want to send everyone in the group a message.

public function connect(url:String):void {                      _nc = new NetConnection();     _nc.client = this;     _nc.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler);     _nc.connect(url);   } private function netStatusHandler(event:NetStatusEvent):void {     switch (event.info.code){         case "NetConnection.Connect.Success":                           createGroup();             break;                      case "NetGroup.Connect.Success":                                //!!! post msg to the group, no one receives this message             var message:Object = new Object;                                message.text = "Hello";                             message.sender = _nc.nearID;                                _netGroup.post(message);             break;         default:                                trace("event.info.code: " + event.info.code);                       break;     }               } private function createGroup():void {     _groupSpecifier = new GroupSpecifier("test_group");     _groupSpecifier.postingEnabled = true;     _groupSpecifier.multicastEnabled = true;                _groupSpecifier.serverChannelEnabled = true;     _netGroup = new NetGroup(_nc, _groupSpecifier.groupspecWithAuthorizations());     _netGroup.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler);        }

After reading documentation I am a little bit confused, if I am using FMS do I have to write some server side code to bootstrap users? And can I use netgroup.post() or I need to call my custom server side function that will go through all application clients and inform them about some action?