Dropdown menu

1 

import mx.transitions.Tween;
import mx.transitions.easing.*;


var numOfitems:Number = 4;
var item_height:Number = 25;
var STARTSPACING:Number = 20;
var depth:Number = 100;


var menuItems:Array = new Array();
function buildMenu() {
    for (var i:Number = 0; i<numOfitems; i++) {
        var item:MovieClip = this.attachMovie("item", "item"+i, depth++);
        item.oY = 100+(item_height*i)+STARTSPACING;
        item._y = item.oY;
        item._x = 50;
        item.id = i;
        item.onRelease = item.onReleaseOutside=animate;
        menuItems.push(item);
    }
}
function animate() {
    for (var i:Number = 0; i<menuItems.length; i++) {
        var curr:MovieClip = menuItems*;
        if (i<this.id+1) {
            new Tween(curr, "_y", Strong.easeOut, curr._y, curr.oY-100, 12, false);
        } else {
            new Tween(curr, "_y", Strong.easeOut, curr._y, curr.oY, 12, false);
        }
    }
}
buildMenu();

Ive created a dropdown menu wich is working properly.

But now my question is:

How to set sort of a Variable to tell flash:
Only item0, item2 may slideOut/slideIn?
Or item0 and item1 for example.

How to set such variable.
And how to control/aply it.

Greetz://
and thanx in advanced