[FMX2004] prototype only moves one clip

1

I belive this is a simple question for people who knows about prototypes.

Ok so i have this prototype where i send this mc to certain x position. But when i try to send TWO mcs at the same time it only sends the last one. Why is that? What to do for it to work on two mcs at the same time?

here is the prototype:

MovieClip.prototype.moveOut= function ( mc, endX ){
	speed = 5;
	this.onEnterFrame = function(){		
		mc._x += (endX - mc._x)/speed;
		if ( mc._x >= endX-5 ) {
			delete this.onEnterFrame;
		}
	};
};

Here is how i call it:

on(rollOver){
	_root.moveOut(m2, 300);
	_root.moveOut(m3, 300);
}