how insert program between receptionqmail

Hi, sorry for no reponse from message above(was in holidays) So, I want to insert program who change the body of mails sent: recept by port (ex:port25) change body and sent by qmail...but I can't find a solution. Is it possible? Thanks in advance

sort mail with qmail

My problem: I have a small server, and I dont want sent too big mail, so I want to sort e-mail BEFORE sending, catch too big mail, grep and convert attachements, re-sent mail with just a pointer to attachement and text/plain. How I can do? Thanks in advance