Expand roles for team members

For large projects it would be nice to have more team member roles or some way to differentiate between the standard roles. For example if there are several members (13) and consultants (14) that are not co-located. They are spread over two cities and in several different buildings. We look to COL to aid on the communication to help in the role description. That is, we want to further describe the role other than just apply a task to the project member or consultant.

What field may we use to describe the role. Is there a field we may use or one that can be created?

This would help us tremendously, in that manner the individual understands their project role, as well as all the team members, all parties involved including our senior executive staff. Plus this will help our supervision so that they are not burdened with email outside of COL to communicate project expectations.