I have 3 girl ratties in a critter nation. I also have a male guinea. Hes currently on top of my dresser and he makes me nervous up there. He jumps around and squeaks so violently at night that im afraid hes going to knock his cage clean off the dresser lol. I want to put him on top of the critter nation as itd also be more convenient because all my pet supplies are on that lower shelf. However, i dont want to stress either group out. Would they be too thrown off by eachothers scents and stress them out? I wouldnt want them to feel like their space has been invaded.