Combo box choice made from button

Ok, here is my problem. I have a combo box that appears on the left with a series of buttons on the right. Each button on the right represents an item in the combo box on the left. Currently the user can choose an item from the combo box and it determines what will load in the next combo box list that appears below it. What I want to do is be able to make the choice from the button on the right as well.

Note: buttons are movie clips with buttons actions assigned.

on (rollOver) {
//Bring to Front Behavior
mx.behaviors.DepthControl.bringToFront(this);
//End Behavior
_root.USA.gotoAndStop(“over”);
}
on (press) {
//Bring to Front Behavior
mx.behaviors.DepthControl.bringToFront(this);
//End Behavior
_root.USA.gotoAndStop(“click”);
}
on (rollOut) {
//Send Backward Behavior
mx.behaviors.DepthControl.sendBackward(this);
//End Behavior
_root.USA.gotoAndStop(“out”);
}
on (release) {
//Send Backward Behavior
mx.behaviors.DepthControl.sendBackward(this);
//End Behavior
_root.USA.gotoAndStop(“out”);
}
on (releaseOutside) {
//Send Backward Behavior
mx.behaviors.DepthControl.sendBackward(this);
//End Behavior
_root.USA.gotoAndStop(“out”);
}

These buttons are imported with the script below:
myMCL.loadClip (“mapLocations.swf”, 5);

into my main movie where the combo box resides named mainCountryRegion.

Anyone care to help me solve this issue? It isn’t a must, just something I thought of and wanted to figure out. Been trying all sorts of things and thought I would ask and see if anyone else wants to try.

Thanks!