Containing/crating a dog..?

When I leave the house, I gate my big dogs (well big for me) in the kitchen where their crates are. One rescue has separation anxiety so he'll pee in his crate if I close the door, or anywhere else in the house if he's not gated. I can still expect an accident 25% of the time, but it's getting better with this method and at least he's peeing on tile. Not a great solution I realize, but I think this is a marathon and not a sprint issue