BHOLD RBAC: dependency on AD

I was going through the BHOLD introduction below and wondering if AD is a dependency for BHOLD for implementing RBAC (since it uses organizational units). My client has an existing AD where the maintain the users, and wondering if they need to create another OU to maintain roles.

Microsoft BHOLD Suite Concepts Guide
http://msdn.microsoft.com/en-us/library/jj134102(v=ws.10).aspx