As weird as it sounds, and obviously do so within reason - but bite the biter back. This is how we handled it with our kids when they went through this phase... we did not but hard or forcibly, but just enough for him to feel what he did to the other child. believe me - it gets their attention and may quickly curb their urge to bit.
It worked for YOU with YOUR kids.
It most certainly did NOT work for me with my kid. I bit him, nowhere near as hard as he had been biting me, and I was watching his face, and I could practically SEE his thoughts. It went from "why does she yell and scream and cry when I chomp" to "oh, all that yelling and crying meant nothing, she actually means we DO bite in this family, excellent, I'll carry on with it then".
NOt sure why his thoughts sounded so British there, LOL, but I truly believe that he learned that we do bite, and it took much longer than I think it would have taken, to stop him after I did that.
Your family has obviously never been bitten by another human. As you know, since you were the first victim, it hurts like nothing else on this planet. My son once bit me on my shoulder blade. A pain like no other. A pain that can ALMOST, but not quite, cause you to forget that this is your child, and not a wild animal, and takes every vestige of brainpower to not react as though it is a dangerous wild animal.
Your family has obviously never had "a biter" near them. Biting kids are vilified, and for good reason. I wanted to send my OWN kid away for the phase of biting! It was awful. Biting kids get that reputation and it never goes away. I still remember the face and name of the kid in my mom's circle of friends who was "the biter".
With other kids in the situation, you just have to be on top of the situation all the time. Never let them get into a position where they will be bitten.
Be aware of his teething patterns, making sure he has proper things to bite on. Also, maybe, and this is only because it turned out to be a causative factor that we realized in retrospect long after, look at his diet. We realized at 3 years old that DS can't handle certain types of sugars (if you turn corn into a syrup and do anything with it, DS cannot handle it) and it turns him into a rage-machine. One of his behaviours during those rages is that he clamps his mouth shut. I *think* that this is what was happening when DS was biting. We didn't KNOW we were feeding him that, I wasn't checking ingredients for more than the usual (we're vegetarian), and honestly he wasn't getting THAT much food-food, since he still was *nearly* exclusively nursed until well past a year and a half, but I think some snacky type things did get through.
So...check his diet, see if he has problems after certain foods. Could be something, might not be...but if it IS a food thing, then it's the easiest way to remedy it.
Otherwise, just constant vigilance and making sure he understands that this is not acceptable.
And stop telling your family if they are going to make ridiculous replies like "kids being kids".