Setting Index for a Background

Hi again. I have run into another problem with my background; I can’t set the index up correctly. Just to clarify, my background is a separate class of pixels (made to represent stars) which is called by the Main class about 10 times a second.

The problem is that these pixels appear in front of everything else, which obviously ruins the illusion of a background, and I don’t know how or where to set up the *setChildIndex *function. Should I set up the index in the Background class itself, or in the Main class? Should I be using a container? (Which I tried but couldn’t get to work.)