I have been using LINE messenger soley to communicate with my game buddies. Even though I have WhatsApp and Facebook messenger, I don't use them since they give away a lot of personal information to strangers I met in game. LINE messenger is becoming less secure since there is no admin feature in groups and anyone can remove anyone. Also there is a case of bots which can remove everyone from the group.
Hence I am looking for a chat app with features like group albums and group posts, with an admin feature. I am thinking like a simple chat app. Because there will be many players of different tech knowledge.
Platform: Android (though a multiplatform would be nice). I don't have a server.