[Zope] Migrating to GRUF sensible, possible?

[Mark Barratt]

I have a Zope site with an (out of the box) acl_users in its root 
containing lots of (700+) users, and a Plone site a few layers down 
within the site, which currently inherits user data from the acl_users 
in the root.

Either using GroupUserFolder (GRUF) at the root of my site and getting 
the existing acl_users into it, or setting up GRUF in Plone so it 
inherits users from the ordinary acl_users above it would make it 
possible to administer users sensibly in both the Zope-only and Plone 
parts of my site.

Plone (2.04) claims GRUF is optional, but I don't think it is.

But I can't see how to do either task, though I have read the book, 
googled around, etc. Is what I want to do sensible? Possible?

Thanks for any help or pointers

-- 
Mark Barratt