Delegated Administrators for single domain multiple COS

Hi,

I need advise on how to achieve this.

I have multiple servers geographically, running multiple domains, multiple COS and multiple administrators.

I want to allow administrators from Country A to administer accounts in their respective servers or COS only, and not be able to administer accounts, or possibly even do not allow viewing of these accounts in Country B or C. Lets say i only need this functionality for a single domain. Is this achievable?

Thanks in advance!
Paul