Isolate the elemnts in separate pre-comps.
Oh I see... so I cannot link the one camera to on spesific layer?
If the layer is a 3d layer, it will be effected by the camera. If it's a 2d layer, it won't. Thus you either need to precomp the layer (and leave the precomp 2d) or you need to make the layer you don't want to be effected 2d.