onRollOver & onRollOut on MC

Hi, I am new to action script and here is my problem, please take a look at my attached test file.

I have a main movie clip on the stage, and 3 sub movie clips are inside this main mc. I want to do some action on the onRollOver and onRollOut on the main mc, i got that working with no problem. In those 3 sub mc, i have the on(Release) script on each of these sub mc to do some action.

However, If I use the onRollOver and onRollOut on the main mc, the on(release) in those 3 sub mc will not execute. Is there any other way to accomplish this? Thank you for any help.