[fetchmail]issusing a QUIT command

Hi,
One part of my company connects to main server (qmail) and downloads 
all the mails over dial-up. Now, with large mails there is a timeout 
problem and mails are retrieved over and over again.
People at qmail list suggested that I ask the client (fetchmail) in 
this case to issue a QUIT command and reconnect after a few messages 
so that those messages will be retrieved and deleted and won't be 
taken into account the next time. How do I get fetchmail to do that?

With warm regards,
-Payal