[Zope] Role Acquisition

Hello all, I have a document that is a few folder layers deep in my site. I want to setup specific permissions for the document in that folder that don't acquire higher level permissions. From what I read, getting the security permissions with python on an object will get local roles, but will go high if they don't exist. I only want to know the local roles. Hope that is clear, thanks for any help! Andrew R. Halko