Authority Tables

We are developing a new software product for internal users and I need to define authority.  I'm just wondering how everyone else is using CaseComplete to define authority based on role? Do you create a definition or add the authority to the actor definition or create a requirement? Use cases and formality is completely new territory for our development team, so I can introduce anything I want as we redefine the look and feel of our business requirements documents. I'm just wondering what the best practices are for integrating authority defintions into Case Complete. I would prefer not to create an external document if possible. - Thanks!!