Linking Exim to a MySQL database to manage conditions for delivery

As a cPanel User, I would like the ability to configure conditions for mail delivery based on a MySQL database.

I would want to create a procedure along the following lines.

1.- A User sends e-mail to another recipient (outside or inside the same server) with a hosted domain (there can be more than 1).

2.- Server detects this e-mail, the domain name, and it knows this domain has a unique procedure (others do not have) and process the e-mail reading a DB (mysql, for example, installed in the hosted domain name).As a result there can be two or more situations (I write these two):

3.- If server (exim) finds a record with this e-mail address with FLAG (yes, or 1) then server deliveries the mail.4.- If server (exim) does not find a record with this e-mail address, or FLAG (no, or null) then server refuse to send the e-mail and create a customized response to the user.