Script doesn't work whenbuttons are grouped into a Movie Clip

This Script:

import mx.transitions.Tween;
import mx.transitions.easing.*; 
var cities:Array = ["muscat", "sohar", "dubai","abu_dhabi"]

function mover (targetX, targetY){
currentX = marker_mc._x;
currentY = marker_mc._y;
var xTween:Tween = new Tween(marker_mc, "_x", Strong.easeOut, currentX, targetX, .5, true);
var yTween:Tween = new Tween(marker_mc, "_y", Back.easeOut, currentY, targetY, 1.5, true); 
for (var i = 0; i<cities.length; i++){ 
*var my_btn = this[cities+"_btn"];
my_btn.myCity = cities;
my_btn.onRollOver = function() {
mover( this._x, this._y); 

…does not work when the buttons “muscat_btn”, “sohar_btn”, “dubai_btn” and “abu_dhabi_btn” are grouped into a movie clip.

Any suggestions?

Thanks :thumb: