Grouper can have objects of different types with the same name. If you are provisioning to a system that cant have this, you might want to enable this hook which disallows it at object creation time:
This checks for objects of type: group, folder, attribute definition, attribute. If an object of the same name and different type is created, it will have a HookVeto exception.
This hook is included in a 2.2.1 patch, though could probably be installed in previous versions of Grouper