[Zope] Can Role include an other Role?

[zopestoller@thomas-guettler.de]

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