Request for User Group State Field

When the Company Organizational Hierarchy changed and some user groups were no longer needed these groups would have been removed/deleted as part of the clean-up process.  With Capacity Planner the User Groups that have Resource Requests linked to them can no longer be deleted.  We need a way to notate that a user group is no longer and "Active"  group and members cannot be assigned, Objects can no longer be linked.  The user group can remain to keep the historical data related to resource requests.