Registration Policy, Multiple Mail Servers, Same Certifier

Hi everyone-

I’ve been asked to create a registration policy, and it is easy enough, but I have one question.

I have 3 mail servers, all of which use the same certifier ID. Do I need to create 3 separate Policies and/or 3 separate settings docs in order to allow the administrator to register a new user on the appropriate server?

We register our users to their home server based on the city in which they office.

Thanks in advance!

Robin