[Zope] Groups and Roles

I understand what roles are but am having trouble working out how to use groups with reference to roles. For example does a group have a role or do people have a role within the group? Or can it be both? I am trying to tie this all in with LDAPUserFolder and the GroupUserFolder but still not "getting it". Any help greatly appreciated. David Orr Development Analyst Programmer Henry Walker Eltin email: david.orr@hwe.com.au