EricNoah
Adventurer
I would try to identify the people who want to play a little more or as frequently as you currently are, and the ones who want to play less frequently or just seem to not be able to make it. Then I would run two campaigns -- one for the smaller, more frequent group (and put your energy and "best stuff" into it), and then maybe run mini-campaigns or one-shots for the whole group when they can make it.