Scenario: new data center. Is there a way to direct QAS clients to a specific pool of domain controllers for service

If I place Linux hosts in the forming cloud, treated as nothing more than a new data center with fresh installed QAS clients, I want to be able to limit which DC's these QAS hosts hit for LDAP/Authentication.
I don't think they will fit the normal AD Site boundary floating as they will - up there in the sky ...
So … is there a command line or vas conf option to achieve this?  For those hosts, I want to specifically provide either an F5 address or round-robin list of targeted domain controllers for regular LDAP/Auth traffic.