i think learning groups are the best post college format to hold someone accountable. I would say i probably know the least od of the three people that i'm talking about it with, but we're all within the same ball park. It feels like we have a teacher goding us, not just a group leader. Try not to have more than eight people in them. You don't want too many people where members start to become inactive or complaisant because they know that people won't notice their participation.