On my last trip I was a guinea pig/groupee for a friend who wants to start doing more guiding. We were a group of ten. I wish I could tell you exactly what she did.
She prepared/cooked all the dinners and it worked great. They were vegetarian/gluten free — with optional dairy (cheese) that we added individually.
She provided water for tea after dinner
She provided hot water in the morning – enough for a hot drink + enough to make your own instant hot breakfast. (though I brought my own Caldera Cone so I wouldn't have to wait in the morning and cause I wanted to show off.)
The best dinner was a Moroccan bean stew. (Though I think i liked that the best because I carried it!) If you're hiking with adults and not pushing them beyond their fitness level, be sure to divvy up the group gear/supplies.
I've also been on group trips where we all used individual alky stoves. That was good for learning, an did have advantages. I haven't done the math, but I suspect group cooking ends up being overall more efficient weigh-wise than individual cooking. I also like the communal aspect to it.
She used a WG stove and one big aluminum pot, looked like maybe 6L. Yes it took awhile, but the pacing worked. I was pitching my tarp and picking blueberries while the water was heating up. Efficiency-wise one big pot might be slower, but is probably more fuel efficient, than separate. Personally I loathe WG and will only use alcohol or canisters. For a group of six, my choice would be a remote canister stove (for stability) and the Open Country 4L pot (so cheap!)
If you just bring one stove it's that much less to carry. If people are high maintenance eaters with requirement you don't want to adapt to have them bring their own cat-can stove and meals.
It helped that this was a very nice group of women. No whiners in the mix, lots of gratitude.
The only negative was there was a hair too much food — and a push to clean the pot. So I ate too much one night in an effort to help. So I'd err on the side of too less than too much, and compensate with snack food or individual additions to the dish (e.g. cheese, chips)
fwiw it was also an older group. We could, and did, eat peanuts. With kids that's another thing that commonly needs to be avoided. (e.g. my kids schools and camps are all nut/peanut free).
Re: the JetBoil — is the group one all vertical, not remote, like most Jetboils? If so I'd nix it for being tippy, but at some point in group size a heat exchanger-if you can find one compatible with your set-up – is probably worthwhile, both in terms of time and fuel weight.