You can add an individual Remote Desktop Session Host server or a farm of identically configured RD Session Host servers ...

You can add an individual Remote Desktop Session Host server or a farm of identically configured RD Session Host servers as a RemoteApp source. RemoteApp programs from the RemoteApp source will be available through RemoteApp and Desktop Connection.

If you are using a RD Session Host server farm as the RemoteApp source, specify the DNS name of the farm.