[Zope] How to publish to a small group of users?

Hi, I'm looking for a way to publish a CMF topic object to a small group of users. What I mean by a group of user is only some members of my Plone Site. My goal is to create privates workgroups, where members of a workgroup share common components (forum, files, events, ...). Thanks for your help. Patrick Gelin Chef de projet RPN Office de la Statistique et de l'Informatique Scolaire Tour Espace-Citée, 4ième étage CH-2300 La Chaux-de-Fonds Tél: +41 (0)32 919 79 13 Email: patrick.gelin@rpn.ch