Coaching projects is not easy, especially when each groups prosesses different topics and the energy momentum of each group is different. Some group work in team really well, and by following the coach's reflection and recommendation, they can progress really good. Some group do not work effectively in team yet. In this case, you need to meet more and really discuss on the topic - the one who is good shall wait and encorage the other on the projects. TEAM work for this type of group is the key and I can see that most of your groups are so. The more you meet up, the better in this case.