GRP-09: Synchronize an external group

Executive Summary: 
A community member needs to synchronize a group’s membership with a group defined in another system so applications that use groups for access control (use cases GRP-12, -13, -14) can reference a group that is primarily managed in another system. E.g., a multi-institution research team uses the Open Science Grid’s VOMS service to define its membership, and an XSEDE L3 service provider at Indiana University wants to authorize jobs submitted by the team. The IU resource is already integrated with XSEDE’s group system, so it would be less expensive and less complicated to use an XSEDE group than to install a local VOMS instance and use it for access control.
User Importance Summary: 
Community members need to be able to define and manage arbitrary groups of people to which they can refer for authorization and communication purposes. In many cases, the groups of people are already defined and managed in another system and our community members need to be able to reference those definitions.
Target Communities and Sizes: 
Community members who participate in externally defined groups - 100 < N < 1,000