conditional bounce

[Mauro Tabl�]

Hi all. I am a beginner qmail user and I have a problem on managing bounce messages that i'm not able to resolve. As you well know, when qmail receives a mail for xxx@my_domain, and xxx doesnt exist in my_domain, qmail reply with a defined message to the sender (Hi, this is the......). What i need is qmail to look if xxx is in a data base (but keeps no e-mail address on my_domain); if it is, then qmail must send a bounce message, with a "specific message" to the sender (not the default message; for example: xxx does not still activate a mailbox in my_domain, .....); if not, i.e. if xxx is unknown to my_domain and to my DB, then qmail must reply to sender with the default bounce message. please help thanks