Interesting debate. As for studies of hamsters in the wild, actual true wilderness is hard to come by, as there are so few hamsters actually living in accessible wilderness...
Of almost my 20 dwarves, 2 RWW and the rest Campbells, I have not had a single fall out. Only with a group of 5, which was a mistake in the first place,as he was the last boy, the albino irritated all the others; so he was separated. They very often huddled together, in sleep or play; eat together. Even in their balls they would congregate in their favourite places. My boys always came from the same litter and from a reputable breeder around London. I found that they 'enjoy' each other's company and look for each other. They also groom each other. A group becomes bit of a problem when one of them dies. But, as they allegedly have short memories, this is not a big problem.
This link will explain how they live in the wild:
Welcome to the British Hamster Association Web Site