Is there a way to make Zibmra to delegate administrator functions for a domain to a particular account? I would like to use have say 3 domains and have a master account that can manage all, and two sub admin accounts that can only maintain their particular domain.

Ideally, you should also be able to determine exactly what administrator functions to permit.. eg, the admin account for a subdomain can setup new accounts, but they are only allowed to exist on the COS that domain, and the admin for that domain cannot define a new COS.