It seems like this one is likely related to your other post here.
If the is_admin_for
relation is a many-to-many, then you need to go through the junction table and you’ll have to go deeper into that relationship.
So the syntax may look like:
$CURRENT_USER.is_admin_for.group
or
$CURRENT_USER.is_admin_for.group_id
Something along those lines depending on your exact schema structure.