OWA 2007 Public folders – Forwarding appointments

Users can add appointments for using the OWA public folders, but cannot invite attendees nor forward any appointments; you can copy to your own calendar, but I can’t find anything that would help give that option to some users.
Does anyone know how to make this happen?
Also, I like to make some of these folders invisible to some users, give specifc rights to groups to view only, or none.
Thank you in advance.