Having a way for worlds to tell is a player is a member of the group that the instance belongs to in a group instance, and what role, would be useful for what I think should be obvious reasons given the existence of group+ instances. The return value could be an int type using simple bit flags to represent what role archetypes the user has (since specific role names would vary by group). For example:

A 0 value would also be returned for all members of non-group instances. If it's always the case that a higher level role has the expected permissions of the role below, a simple incrementing int could be used instead, such that:

Regardless of implementation, some way to tell the broad relationship a user has to the group in a group instance would enable more straightforward and easily integrated settings for worlds to implement to allow groups to manage event hosting, meetups, etc.

Combine this with the ability to get the instance type ( https://feedback.vrchat.com/udon/p/request-instance-type-nodes ) and whether or not users are friends with one another ( https://feedback.vrchat.com/udon/p/isonfriendslist-for-worlds-udon-soba ), and you've got the dream team for worlds building up on the social integrations VRChat provides.