Remote Desktop Services access restriction via IP

Hi All,

I have a remote desktop deployment which consists of RD Connection Broker, RD Gateway, and RD Services or Terminal servers, all run on Windows Server 2012 R2

The deployment works well, access is granted via an AD groups

My question is if its possible to restrict access to these groups to the RDS deployment via an IP address or a range of IP addresses, NPS is installed on the Gateway but i don't seem to be able to get the right settings for this to work, are their any guidelines for this?

Thanks

Mic