Critter Nation question

I assume you meant if you could keep females in the top and males in the bottom?

If so, then yes. I'm currently doing that myself. I have 5 females in the top and 2 males in the bottom waiting to be neutered. All my rats are very young though, I'm not sure if that really makes a difference. They're all very happy silly ratties and I haven't had any issues.

It really depends on age and the hormones that are there. They might be interested and annoying for a while, but as long as they're securely separated, it shouldn't be a problem.