Telegram is good. You can have group chats or set it to delete everything every 24hours. It can also let you know if guys take screenshots if you don’t want info leaked.
I’m not familiar with it. Isn’t it sorta like Wickr? Be cool to have a site where you could create threads. Like instead of one big place with an endless amount of reports we could categorize by source, product, etc and also have a general discussion thread.