Adding Client Machines and Member Servers to Domain in a Site with no PDC and RID

We have a domain spread over different sites. We are not able to join XP, Windows 7 client machines and Windows 2008 R2 servers to our domain in a Site that has its own DCs which are not PDC or RID. When we shift the PDC and RID roles to a DC in that site the clients are able to join the domain.
Is there a way that the client machines and servers could join without the Roles Transfer to the specific site's DC?