Authenticate web users and hide from address resolution

I have a requirement to register a couple of thousand users to access a secure application.

As these users will not have any email, I do not want the user name to be available for name resolution when addressing.

I am happy to put the names in a secondary directory and link this in using Directory Assistance. This works for authenticating the users but I can address mail to the users and the address book is available for name lookups.

Is there something specific I need to do with my config, do I need to take an alternative approach, or is this not possible?

Thanks

Subject: Authenticate web users and hide from address resolution

Chris,did you find any solusion for your case. I´m in a simular situation.

Please let me know about your experience.

/Sune