Implementing Filter-Id's with MySQL

Hi, I am running a Freeradius server which queries a MySQL database (Vexim) for authentication of dial-up users. I would like to create two classes of dial-up users, Internet users and email-only users. The Intetrnet users have full Internet access while the email-only users can only access SMTP, POP and DNS services. I am using a Livingstone Portmaster 3 NAS, and will create a filter, emailonly.in to manipulate the IP traffic. My question is, how do I configure Freeradius/MySQL to add the Filter-Id attribute to email-only users and thus deny them full Internet access. Regards, Tawanda --