Cats fighting

I have 5 cats, all of them altered. The oldest male, Sly (8) the oldest female ,China (9). 2 other neutered males,Tyke & Chub, & a female,Petunia, these last 3 are from the same litter, all over 2 yrs. old.. Sly,, here first, China here 2nd. Then the litter last. They have all grown up together on a farm. They all sleep in the same room at night, no problems, but outside, a different story. Sly is always 'gunning' for Tyke,they almost kill each other. Then Tyke is always 'gunning' for China. They have real bad fights, this is not play. Out of the whole bunch, Tyke is the only one who 'marks ' territory. It is becoming very frustrating as they do get injured. At this point, is there anything I can do?