The use case i imagine, open to watch but permissioned to write communities. Facilitated by relay feeds.

group A, group B, write to their own set of white listed relays independent of each other. Conversational and communtity "security".

Group C pulls in events from both group A and B, comments on their content and extends the work done, but only on their relays while A and B can do whatever they want without being intruded on or having their signal muddied by thousands of forks, edits and comments they don't care about.