That's one of the reasons I built GroupTweet. To facilitate private group communication on Twitter with any number of participants that can persist through permanent Twitter accounts (instead of temporary Group DMs that are limited to 20 people).
Would love any feedback or suggestions on how it could be improved.
Happy to offer free use to anyone on this thread looking to test out the service.
Twitter's open communication channel might not be suited for such infoshare. Telegram/Whatsapp has potential in that area.