Baby Gates

I'm having issues (big surprise) about how I am going to install baby gates in my house. The problem really is the dogs. They are too dinky to jump over the gates, and I know that if I put them up and they aren't able to run around the house like they are used to, they are going to make my life a living hell.

The biggest problem is that their potty-spot is upstairs in the guest bathroom (sorry guys), so the gates on the stairs are going to seriously interfere with them going to the bathroom. And if we leave them upstairs, they will cry and whine until we let them down again.

I did find these baby gates that have a little door in the bottom that the dogs and the cat would fit through, but I can't put it at the top of the stairs because they are pressure mounted. Maybe I can just drill them into the walls anyway? I knew we should have bought a one story house. Crap.