[Zope] Authorization by Hostname or Address

I have read and applied the Zope "How-To" concerning authorization by Hostname or Address at : http://www.zope.org/Members/muesli/AuthByAddress It works, but I would like to be able to open up access for a whole domain without having the user being requested to type in a login, even if there is no password control. Is there a way to create a kind "anonymous" user in a "User Folder" who would only have a domain restriction and no "login" atached to it? It seems that any user has of course to be created with an id and hence this id is being requested as the login. Pierre Godefroy