Function Help

Hi, I need a little help writing a function inside of a button. Here is my current code:

on (rollOver) {
box_1.loadMovie(“over.swf”);
}
on (rollOut) {
box_1.loadMovie(“blank.swf”);
}
on (release) {
box_2.loadMovie(“blank.swf”);
}
on (release) {
box_1.loadMovie(“expanded.swf”);
}

Somebody awhile told me that I should not have two (2) “on (release)” calls within one button but I cant seem to find a way to write a function for both of these. If anyone could help me I would really appreciate it.

Thanks,
Brian