Is there anything one can read to better understand the “upper level” communication?
The disjoint groups (now known as disjoint sections) RFC is probably a good starting point.
It may be a bit dense, but hopefully it can get you started.
For some discussions on this forum: RFC: Disjoint Groups - #21 by JBishop.
And if you have any question while checking these resources, feel free to ask 
6 Likes