I've got a father and son that have lived together all their lives, they also live with a colony of about 10 females, they live in a huge cage, and i think that's the key, if there's enough space and maybe even enough females to go round then there shouldn't be any probs. They have never bickered or scrapped, the father is getting on now, so only time will tell if this will have an effect on anything but it already appears the son is dominant as hes a lot bigger, bulkier and generally alfa-looking!
I also have a tub of about 30 males together that are ones that are homed or for sale, two thirds of those are mature and ready to breed, also a few of them are multi-mammates, sometimes there are squeaks and bickering over dinner time, but never a fight and never any harm done

but without females i suppose theres less chance of a fight breaking out, although the girls are just in the tub next door so they can still smell them...