[Zope] Can Role include an other Role?

I have three groups of users: A, B, C. C should have all permissions that A und B have. How can I do this? Example: +All members of A are allowed to delete files in "foo", B member are not allowed --> C member are allowed If A, B, C would be users it would be no problem. But they are groups I read the the security chapter of the zope book on: http://www.zope.org/Members/michel/ZB/Security.dtml But I couldn't find a solution to that. Platform: Zope 2.4.3 on W2K