Hi Lawrence,
What exactly is what you want to know.?
Do you wish to maintain roles with the help of GRC?
BRM is there to address role maintenance to the backend connectors.
BRM will help you to create or maintain the roles from the scratch well as to maintain the roles which are already available in backend systems.
It all depends on your business needs.
So be specific and clear to where exactly you need help.
Regards,
Ameet