Well, I've written some 35,000 words on Jean Prouvaire acquiring a pet goat, losing it in the midst of the turmoil of the 1830 barricades and Bahorel carrying both the goat and a recently-shot-in-the-shoulder Combeferre to safety - but that's just me.
I think it's reasonable to see them as having been something of a cohesive unit at the time. They're introduced as being a de facto group in 1828, so one would think they might go off to the barricades together or at least with the anticipation of meeting up somewhere near the same place and possibly getting separated in the heat of the moment. The only one I can really think of who might by intent not be with the rest of them is Bahorel, since he has so many affiliations to other groups, it's not unlikely that he might have joined up with some of his other friends.
Grantaire might have joined in with the general fervor of the moment. I've always sort of thought that if Enjolras had asked him to, he would have put forth some show of trying to be helpful at the 1832 barricade. But because he felt he'd been snubbed and was being sulky, he drank himself into a useless stupor. I think this could go either way if you wanted to write it. Marius probably wouldn't have had such an active role. Around this time he'd sort of split ways with the group as a whole and even in 1832 he didn't exactly go to the barricade to help out so much as to get himself killed because boo hoo, Cosette's leaving.
"Quand vous aurez besoin de Bahorel, capitaine, Bahorel est là! Je sais faire trébucher tous les chevaux du garde-corps avec une ficelle... Rien qu'une petite ficelle. Enfin, pensez à Bahorel du Café Musain!"