Assuming that they should be bite sized is a mistake, because the best "intimate sharing between exclusive groups" message might actually be long and detailed. Go look at how exclusive groups communicate now, and model your design to promote those qualities that you find. The problem is you're saying "I want them to be bite sized" not "exclusive groups tend to send bite sized communications."
Good point, I will do some further investigation :) I am trying to create a more exclusive groups product, but I want to keep information sharing to quick bite sized chunks. I guess that might not be a solution though.