Ok, I have an idea for you, and quickly... psped it.
So Reeses would be grey, Bailey greenish,and the girls, purple.. Black=Ramps.
You could add another level in between the boys 1x2 each. So a 2x2 in the middle of the 2 2x4s with your girls still on top. That would give the boys their own spaces, with access to seeing eachother through the girds, and it wouldn't take up any of their origional 2x4s space.