Inactive Users

As the site ages we have many profiles for people that most likely will never use the site again but we don’t want to delete their data. The problem is that their names show in the list when assigning courses, etc. As you can imagine, the list can get quite long if filled with inactive users. How can we display only desired users. Currently we have a different “role” for inactive users so if we could specify the appropriate role(s) that the system should use, we would be all set