I just started using nostr:npub1tm99pgz2lth724jeld6gzz6zv48zy6xp4n9xu5uqrwvx9km54qaqkkxn72 today and it has group chats. nostr:npub1h0uj825jgcr9lzxyp37ehasuenq070707pj63je07n8mkcsg3u0qnsrwx8 also has group chat. I think the group chats in 0xChat are public while the ones in keychat are private.