I think the bottom line of all the advice gathered here and given in private, is that the OGS chat really isn’t the best medium for what you want, which seems to be long term group discussions. OGS chat is mostly there for short banter.
There are several options that are far more dedicated to having organised discussions in group setting, among which:
- A private thread here on the forum, which is still native to OGS (not optimal, but better than the OGS chat)
- Discord or Slack is specifically made for communicating with a group, and have options to create separate channels, restrict channels to certain members, moderate chat, file sharing, voice / video communication, and of course most importantly: chat is persistent
- If your go club has a website, you could considering installing a forum on your own site. That way you can organise topics more clearly and have all the freedom you need.
I strongly recommend to move your go club conversations to one of these places, and let the OGS chat for what it is: short idle conversation.
Our forum uses discourse, you could take a look at their site to find more about it.