Managing display list

Hi, I have some trouble with the displaylist in AS3.

In my project I have 3 types of elements that spawn at different times.

  1. When I hold the mousebutton down object 1 appears.
  2. When I release the mousebutton, object 1 disappears and object 2 spawns
  3. At regular time intervals yet another object spawns, object 3.

These objects might (or will rather) touch eachother at some point. And what I want is this:

Object 1 to be under object 3 and object 2
Object 3 to be under object 2.

In other words: Object 2 needs to be on top, then Object 3 and lastly Object 1.

How do I go about doing this?