Off topic, but plenty of people here run build groups.
A few of us started a chat server for people building cabinets and control panels, mostly sharing progress photos and wiring questions. It is around 600 members now, and most of the regulars came through a few builders who keep inviting friends from local meetups.
We wanted to give those builders a small role. The default invite numbers were useless, since anyone who joined to ask one question and left still counted. We ended up using a bot that only counts members who stay, and the list finally matched who everyone already knew.
Do your groups track this, or is it not worth the effort?