Forum OpenACS Development: Actually Using Groups with nested subgroups?

I am working on a site with a "main" membership group, with different
sub-subgroups such as "writer", "editor" etc.  Since the distinctions
between the groups are quite strong and there are many users, it makes
sense to leverage the groups code for this.

Assume a structure like
(Registered Members) (main group)
-(Content Production) (sub group)
    -- (Writers) (sub sub group)
    -- (Editors) (sub sub group)

My main question concerns the use of membership_rels and
component_rels.  What exactly, are these and how do I use them
properly?  The documentation I have describes them but does not give
any examples of how to use them.

Right now, I have both Editors and Writers as components of Content
Production under the "composition relation" part of the admin UI.

I have nothing under the "membership relation" side - do I need to add
anything here?

Also, under the example shown above, will a member be able to be a
member of the Content Production subgroup without being a member of
one of the sub sub groups?  Do we need to create another subsubgroup
or add anything to composition relations for this to happen?