I brought in a barn cat so she can enjoy life as a house cat. I set up her litter box in the closet of my office and bought a pet gate with a small door thinking it would work to keep my dog out of the litter box. However apparently they only work in wide areas, in the doorway it doesn't expand enough to allow use of the pet door so am returning it. Any thoughts on how to block the dog from the litter box? The door to the closet btw is not a normal door, it has panels and would be pretty much impossible to put a cat door in. TIA