I have to crate my two together. If they are crated seperatly they will bark and howl in agony until either released from the crate, or put together in the same crate. I have a Big Paw, and a tiny paw though, so it's easier for me to do that. With two Saints, it might be a little more difficult, unless you have an actual room you could designate as their "Doggy Den". Another thing you could try, which is something that I know some other BPOers do is place 2 crates side by side, so that they're in their own crates but still together.
Good luck!