Licensed users on Enterprise, Business, and Education accounts can host up to 2 meetings at the same time.
Both meetings need to be started by the original meeting host and cannot be started by an alternative host. The host can leave the meeting and pass host privileges to another user if needed.
Read more: Can I Host Concurrent Meetings? – Zoom Help Center
If you need to host more than two meetings concurrently, then another licensed user will need to host it.
If you need 4 buttons, each one corresponding to a room, I recommend setting up 4 users and 4 meetings (one for each room) and assigning each button a different meeting ID. It will be easier to manage this way.
I hope this helps,