Someone

    class MainRoot
    {

            public var container:Sprite = new Sprite;
            
            public function MainRoot()
            {
              
                    addChild( container);
            }
            public function SummonArmy()
            {
              
                    pasukan:Army = new Army(this);
                    container.addChild(pasukan);
            }
    }
     
    class Army
    {
            public var stageRef;
            public function Army(_stage)
            {
                    stageRef = _stage;
                    trace(detekTemanSeperjuangan());
            }
            public function detekTemanSeperjuangan():int
            {
                    var countUnit:int = 0;
                    for (var i:int = 0; i < stageRef.container.numChildren; i++){
                              countUnit++;
                    }
                    return countUnit;
            }
    }