The current implementation of the saml_admin_attr limits to a unique attribute name, however, if multiple Organizations are mapped with SAML you cannot limit the admin role to the attribute values. Currently admins only allows the username/email.

{"saml_admin_attr": "admin-of"}

Suggested fix:

{ "saml_admin_attr": "admin-of", "Test Org": { "admins": ["groupname"] }}