The AARC recommendation AARC-JRA1.4A-201710.pdf is about expressing group memberships in a standard way, particularly in SAML using the eduPersonEntitlement attribute. Seems most related to XSEDE use case GRP-09 (Synchronize an external group), under development in XCI-45.
Potential discussion topics:
Interop with Globus groups
Other protocols (OpenID Connect, SCIM, LDAP)
Motivating use cases
There are comments for XCI-257 that can be viewed with XSEDE authentication.