Help making a "starship with lazers" game

the starship in my game has some lasers witch are created using duplicateMovieClip, each one on diferent levels. and they should destroy a randomly created object that they hit.
i’m trying to do this by using hitTest, but I can’t get it to work, because the instance names of the movieclips created are changing with each frame…

—Syntethised:

  1. Is hitTest affected by detph?
  2. Could someone suggest me a method to make the lasers destroy the randomly created targets?