POP3/SMTP on Ubuntu using Linux group

I need to setup a POP3/SMTP server on our Ubuntu server (example.com). Now I found postfix useful for this job. Is it possible to let users from the group users (on the system) use this service, so they can 开发者_JS百科login with their username/password? For example, if kevin is a user from the group users, then he can login on the POP3 server and retrieve (and send) mail for kevin@example.com? Is it also possible to save the in- and outgoing e-mails in a database?

Regards, Kevin

Here ís a link to the Postfix features. I have only found that they store users in the database.

I am using a mailserver configured after the tutorials of workarounds.org and have also implemented servers following this solution for a few clients with up to 100 concurrent users for now.

But for example the DBMail project offers at least storing mails to databases.