Can one camera be the background layer for 2 others?

I'm doing a skybox for Oculus Rift, where I have 2 background cameras and 2 foreground cameras (the background cameras simpley rotate the same as the foreground cameras, do not translate), and they look into a skybox in a different layer. Both background cameras are at the same point (not separated by eye distance). So they draw the same thing.

So the right eye camera takes up the right part of the screen, and the left eye camera takes the left part of the screen (side by side stereo).

I'm wondering if I can get away with just one background camera, some how, to have it render to both the right and left parts of the screen, to save having to draw that extra camera.