Just like Yahoo messenger, the Squirrel chat app supports to create separate rooms for specific people or the room to chat the same type of topics. The main room chat room allows for announcements that can reach group-wide. The Squirrel app support to share photos, documents, or links.

What can I use instead of Yahoo Messenger?

The best alternative is Telegram, which is free. Other great apps like Yahoo! Messenger are Signal (Free, Open Source), Element (Free Personal, Open Source), Jitsi (Free, Open Source) and Skype (Freemium).