Overlapping MovieClips and Roll Overs

Hey, first time posting here but these forums have been a godsend to me for a while.

Basically, I have a project with over a hundred movie clips placed on the stage that play a different sound when you roll over them. The effect I’m trying to create is when the mouse cursor is near two or more of the movieclips, it will play them all.

The way I’m attempting at the moment is to have an invisible boundary around each movieclip, that extends the rollover zone so when the mouse is near, the sound plays. This all works apart from when you hover over an area where two boundaries overlap, it only fires the rollover for the movie clip that has the higher index.

Is there a way of detecting a rollover on a movieclip that is behind another one on the stage? Am I approaching this wrongly or could there be something else causing this problem. Would be really grateful for any help, or any alternative suggestions on how I could do this.

Cheers guys.