To grant a delegated admin the group reference right:

  • Run dsconfig with the create-delegated-admin-resource-rights option.
    dsconfig create-delegated-admin-resource-rights \
        --rights-name DArights  \
        --rest-resource-type groups  \
        --set enabled:true  \
        --set admin-permission:reference  \
        --set admin-scope:all-resources-in-base 
The admin can see the user's group memberships on the entry preview's Group Membership tab.