I can understand your reason for being reluctant to split them up but once they've started to fight to the point where they're drawing blood, things don't tend to improve.
Hamsters can inflict very serious injury on their cage mate during a fight and things can progress into a serious fight very quickly and without much warning. As Cypher says though, robos generally do okay in smaller spaces so it's far more beneficial to separate them entirely than to try to keep them together. As Amity suggests bin cages can be an option and if you put mesh in the sides they can stack so you won't have to find two spaces in the room for their cages.
I had to spilt up my first two Chinese after about six months together and whilst one of them seemed a little lonely to start with, he soon adjusted.