There is a minyan in town that has shachris before it gets light because people need to go to work. I have no need to do shachris so early, and there is a minyan in town that does shachris in the proper time. The pre-dawn minyan needs me for a minyan. Should I join them? Does it make a difference if there are 3 of us that they are asking to go early as they really only have 5 or 6 that need to leave for work pre-dawn?
This is an interesting question.
If this is your regular shul and regular minyan, as I understand from the question, I think it is right to join them for the pre-dawn minyan.
Although this is bedieved, if most of the minyan has no choice in the matter, the time of davening is determined according to the majority, and the minority follows them — even if this is bedieved.