Well, you could put a second cage in the house, or put a roof on the outside one.
Other than that, small doses of togetherness, maybe outside the cage (in neutral territory) might help. Or a barrier inside the one cage so that can't get at each other, like a screen of some kind.
I am not so sure you want them together tho. Remember what they say about rabbits...you might be needing a lot more than just two cages pretty soon....