XSEDE's Cyberinfrastructure Integration area (XCI) recently published new use cases describing how XSEDE personnel and community members need to manage and use group definitions. In its simplest form, a group definition is a list of people that needs to be maintained and used for some ongoing purpose. Typical purposes include access control, communication, and project management. These use cases were derived from a project-wide user needs study conducted in early 2017 by XSEDE's Requirements Analysis and Capability Delivery (RACD) activity. Publishing the documents in the University of Illinois' IDEALS archive ensures that a public record of these use cases is available for future participants and for use in follow-on activities.