Actionscript Rollover

Hi! I have this page that has 8 movie clips, and I want to make these movie clips function as buttons. I got that part done already, but what I need now is the Rollover part. I made one separate animated movie clip that’ll function as the rollover, so whenever a button is rollovered the animated movieclip will play on top of that button. So my question is how do you designate the one animated rollover movieclip to play on top of each separate button when they are rollovered on? Hope it’s not too confusing to understand. Thank you!