Dragging Object in Array - Which One?

I have an array of movieclips and have set up my game so I can drag any of them. I cannot figure out, when I pick one to drag, how to identify it so I can do logic on its x and y. I bet there is a neat way but I don’t know enough to zero in on it. Thanks.

To clarify: var obArray:Array = [ob0,ob1,ob2,ob3];

When I drag, how to get number of array element?