[F8]2 Attached movies' hitTest

So, I have in my vertical shooter game a bullet and a flag (enemy) that are attached properly and fly up and to the left, respectively. I am able to delete both the flags and bullets when they go off screen, because I know how to say:
_root.enemy.onEnterFrame(){
this.deleteMovieClip();
}
The problem arrives when I want to connect the two. How would I code a hitTest between one of the bullets and one of the flags? I uploaded my fla here: http://www.megaupload.com/?d=H4LBGTHE