you can keep rams together regardless of breed.
They are probably all okay together out of the breeding season, but you do need to be a bit more careful as tupping time approaches, particularly if there are any ladies nearby.
Do not put horned tups with unhorned - or even in the field next door. A Swaledale will jump a wall or fence to kill a Blue-faced Leicester when the hormones and pheromones start flowing.
Do not put aggressive tups with passive ones of a different breed. An aggressive Blue-faced Leicester will probably accept a passive Blue-faced Leicester, but could easily kill a laid-back Texel.
Take care introducing new tups to each other, no matter what the breeds, once the breeding season is starting. If you must mix them, pen them tightly (no room to back up and ram the pen sides) next to each other for an hour or two, then very tightly (no room to move at all) together for an hour or two, then give them a little room to move around each other but not enough to back up for a powerful ram, watch and if all seems okay, a bit more room, and so on until they are ok together with plenty of space. Then put them in a field where they can get well away from each other - but watch very carefully for a while, as if they can get away from each other they also have room to back up for a killing ram!
raygezer, were you meaning you wanted to work two tups in the same field together? How many ewes and what breeds of ewes and tups?