External MC loaded on Stage, I can press buttons that are on the stage through it

An external swf is loaded using this code…

on(release) {
	loadMovieNum("supplimental/external.swf", 500);
}

The problem is that even though this external movie covers the whole stage, My mouse can still “see” buttons that are on the stage, and I can click them. I don’t want to be able to click the buttons through my external movie. Thanks for any help.