Button to start movie

[FONT=arial]Hi, this is my first post on here and I hope that someone can help me out.
I have a movie clip with a button inside of it and inside of the button the “down” a movie clip inside that. I was hoping there is some way that the movie clip inside the “button down” could read other movie clips and make them change into even other movie clips… basically it is like a shooter that is continually on and the enemies which are bugs get sprayed and then explode. Any help??? I am not sure to use hitTest or whatever. Thanks![/FONT]