I talk them and tell them to be nice to each other and they listen lol

Seriously I handle my lizards a lot even wild caughts, so that within a week they are usally quite nice. So I would have to say I personally feel that the more tame they become the more toned down and gentle they are to each other.
I observed them so much over th years having a few free roamers, but letting groups of collards out each day for a romp along with the roamers.
The free roamers would run so fast, jump off thier basking stack of slate, and right up to the face of the new comer or collared I just put down for a romp (as if to check him out) and the one I just put down would be submissive, until the free roamer (which owned the territory so to speak) was done sizing him/her up. After a few tongue flicks all was okay and the new comer on the floor was allowed to jump on the pile of slate to bask.
This happened time and time again. Some they would recognize as regulars , some had to go through the checking out stage. But I never saw any fight.
And to be honest , YES, I have some 40 breeder wide tanks with a couple males in there. No one seems stressed or fight, normally they just bask together. But I also know people who do have males that fight, so I guess it does help to talk with them and express your wishes for a peaceful reptile room, hehehhee 
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PHEve / Eve