I don't have 2 male pyrs, but I do have all male dogs. Max, my IW is not neutered, but my pyr and TM are. The TM is my dominant dog and doesn't allow any escalation of play into fights between Max and Jake. If their play turns serious, he walks up to them and they stop. Lots of people who use pyrs as LGD have numerous dogs together, with no problems, so I don't see why it would be a problem, as long as you are able to handle it, if it happens. Fighting between most dogs within a given pack, is all about dominance anyway. Just my 2 cents worth.
Kathy