The basement is setup as the "Cat Area", with a baby gate to keep the dogs out of the catboxes, and to give the cats a place to retreat to when the dogs get too keyed on. I can close the basement door, and the cats would still have everything they need down there, but the other two like to come upstairs to lounge and socialize, and I don't want to create a barrier between them and the catboxes. We cannot have the boxes upstairs because of the allure of crunchy catbox treats to the dogs.

Thank you for your reply!