Alpha fade function help pls

hi, just getting back into flash and am trying to learn how to make all my action exist in the main timeline and cut down on stupid repeating.

the code i’m using is for 2 buttons that effect 2 other mclips so that when one button is rolled over it plays the mclips animation and then plays the head back again on rollOut. see below:

functions created:

navItemOne_mc.onEnterFrame = function() {
if (navOneFade) {
navItemOne_mc.nextFrame();
} else {
navItemOne_mc.prevFrame();
}
};
navItemTwo_mc.onEnterFrame = function() {
if (navTwoFade) {
navItemTwo_mc.nextFrame();
} else {
navItemTwo_mc.prevFrame();
}
};
button actions:

on(rollOver) {
this.navOneFade = true;
}
on(rollOut) {
this.navOneFade = false;
}

any help hugely appreciated. even a hand on TweenLite usage instead of these clunky functions - anything basically. don’t hate me cause i’m stupid.