ActionScript 3.0 :: Loading MovieClip On Top Of Main Stage

I'm new to AS3, and am having issues loading external swf files so that they appear on top of entities on the main stage. My main stage is an interface, and as buttons are pressed, external swf files are loaded. Some parts of the external swf files are meant to display over the interface, but they are under it.

Here's my code:
var _dummy1:Loader = new Loader();
addChild(_dummy1);
var url:URLRequest = new URLRequest("external.swf");
import flash.events.MouseEvent;
Button47.addEventListener(MouseEvent.CLICK,bClick3 );
function bClick3(event:MouseEvent):void {
_dummy1.unload();
_dummy1.load(url);
}