[джонатан]

Поковырялся, разобрался, придумал.
Вот, если кому понадобится:

package  {
 
	import flash.display.Sprite;
	import flash.net.LocalConnection;
	import flash.text.TextField;
	import fl.controls.Button;
	import flash.text.TextFieldAutoSize;
	import flash.events.MouseEvent;
 
 
	public class Main extends Sprite {
 
		private var count:int = 0;
		private var connectionName:String = "myConnection";
		private var localConnectionSender:LocalConnection = new LocalConnection();
		private var localConnectionReceiver:LocalConnection = new LocalConnection();
		private var slaveConnectionsIDS:Array = [];
 
		public function Main() {
			localConnectionReceiver.client = this;
			connectReceiver();
 
			if( count > 0 ) {
				localConnectionSender.send( connectionName + "0", "slaveInit", count );
			} else {
				var button:Button = new Button();
				button.label = "send";
				button.addEventListener( MouseEvent.CLICK, sendMessage );
				addChild( button );
			}
		}
 
		private function connectReceiver():void {
			try {
				localConnectionReceiver.connect( connectionName + count.toString() );
			} catch( error:Error ) {
				count++;
				connectReceiver();
			}
		}
 
		private function sendMessage( event:MouseEvent ):void {
			for( var i:int = 0; i < slaveConnectionsIDS.length; i++ ) {
				localConnectionSender.send( connectionName + slaveConnectionsIDS[ i ], "messageFromMaster", "myMessage" );
			}
		}
 
		public function slaveInit( slaveCount:int ):void {
			trace( count, "init:", slaveCount );
			slaveConnectionsIDS.push( slaveCount );
		}
 
		public function messageFromMaster( message:String ):void {
			var tf:TextField = new TextField();
			tf.text = "message from master swf: " + message;
			tf.autoSize = TextFieldAutoSize.LEFT;
			addChild( tf );
		}
	}
}

Прикрепляю исходники.

Объяснять сейчас влом, если надо, пишите, расскажу.