[kyrilliondaemon]

If you've already tried two wheels, two bottles, no shelves e.t.c then you may find that taking some toys and items out of the cage temporarily can help. If needs be you can remove everything, just leave them with a large pile of bedding, scattered food and two water bottles for a couple of days. If the trouble stops then you can start adding toys back slowly, if you add things one at a time every few days you'll be able to see if any individual item is the problem. If they start to fall out again then remove whatever you just added, give them a few days and then add something else. If they continue to not get along even without anything in the cage then you could try moving them to a smaller cage temporarily and see if that helps stop the problems. Once they're getting along well then you can move them back to the bigger cage and start adding toys slowly as I suggested above. I have taken these steps with dwarf pairs/groups in the past and they can work brilliantly sometimes.

I would advise that you check both hamsters daily for bites, if blood is drawn then it will be time to separate. Once blood has been drawn once there's a much higher risk of it happening again and it could easily be a lot worse the second time.