[Zope] Get all user folder instances

[Garito]

Hi
I'm try to know the complet list of users in a Zope point with this 
structure:

root
    acl_users (user folder)
    Folder1
       acl_users (Pluggable user folder)
       Folder2
          acl_users (Another user folder)
          Object1
          Object2

how could I retrive the list of user folders (in this case: /acl_users, 
/Folder1/acl_users and /Folder1/Folder2/acl_users)

It would be perfect something like: Object1.superValues('User Folder')

But this only retrive User Folder's not Pluggable user folder's nor 
Another user folder's

Is there any kind of method to query for security list of users?

Thanks a lot!!