Code to change the depth of a sprite/Movieclip?

Hey,

Is there actionscript code to change the depth of a sprite on the stage?

I’m currently working on a small little project where I have 4 circles rotating around. When objectB hits objectA I want objectB to appear in front so I want that to change depths to the highest depth. Then later on in the animation I want objectC to appear in front of objectB and so on. Creating a 3d illusion of the 2d sprite rotating around.

Any examples too would be excellent.

Cheers!