RDP licensing overload

Server 1 (server 2008r2) has AD and RDS roles and was originally the "single" server for all data. 30 user remote in to access data almost 24/7.

Finally upgraded and added 3 new servers (2 server 2008r2 and 1 server 2012) to the domain.

Now all users are "authenticated" by Server 1 and each server has its own RDP roles installed. So now each user logs directly to the data server they need.

Do I point the RDP licensing to Server 1 or does each server now need to license the RDP users separately?

Now that there is a 2012 server in the mix, does that server need different RDP?

NOTE: Server 1 will be replaced in the near future and NO ONE is accessing Server 1 via RDP except the Admin (me).

Thanks for you time.