Flatten all Element

As you can see in the picture attachment…

I want to giving the glow into the skin of face inside my rigs… so I used color-override and choosing only read my skin colour…
but then the program read the entire of head, some of the head supposely be hide by the hair because the hair is in front…

so then I was thinking this can only be work if I can flatten all element in one, like composite…but composite cannot giving what I want…

is there any module like composite that can make all element really flatten into one just like single element? I was tried glue module, but its not good…

thanks…

open the composite properties of head module change the node to bitmap and input ordering to 2d. that would solve your problem. Cheers!