i keep beardies together, but spend alot of time introducing them slowly before they live togther full time.
my beardies have never torn limbs or killed each other. i did once have 2 boys have a little fight, but its like having a pack of wild dogs, one has to be alpha and the other males must submit and everyone can live happily ever after. the 2 boys i put together one is dominant and one is very submissive, so i knew it would work out. and it did they have been living together for a year with only one fight small fight in the begining.
with my 3 females and 1 male 10 month to 18 month olds i have never had a fight, as long as they have heaps of food and space their is no reason to fight. plus personality is a big factor. all are great and non agressive to each other.
though beardies don't need friends and can live happily on their own and if they clash then you need 3 enclosures.
keeping beardies together is not recomended to an inexperienced keeper.