Fight at our house, its a free show

I am absolutely fed up with fights. Everyday there seems to be a reason they have to get into it.If they're not yelling at one another, they're beating the crap out of eachother. Seriously. Maya gets really smartie pants with Emily. They literally get nose to nose and scream out their issues. Elijah gets so angry he gets red all over and will scream something like this,"You stupid idiot!" or "freak!" He learned all these wonderful words from his cousin. So he'll scream and scream, and if things aren't going his way, he resorts to kicking the crap out of them. Ian is physical, he starts swinging when he's mad our his feelings are hurt. Mario is a little bit of both, but overall he's a little more tame. So, it seems that everyday their is some kind of issue and I'm standing there watching and screaming, "what is going on?" Then you have to seperate them , figure out how it got started and deal with it. So, my question now is at what age do I let them duke it out. My brother said he was like 12 him and his cousin would get into it, and his cousin's parents would draw a circle in the dirt and tell them work it out. So, they would get in the "ring" and "work it out" and then afterwards have a beer. Wait he was 12 , yea, he was already drinking beer, anyway he says, you have to let them resolve it on their own minus the beer. I know one thing for sure I'm tired of being everybody's referee. Obviously my little ones have to be guided when they are upset, but my older I may just draw a ring in the dirt. Mario is always telling that this will never stop, I hope he is wrong. I hope I get a little more sanity the older they get.