Suppressing Bounce Messages

[Manvendra Bhangui]

I have a problem on my site where lot of my users who have subscribed to external free subscriptions are no longer there. Due to this around 80000 bounce message are getting generated daily and clogging up my queue. Is there any way to silently discard these messages without generating a bounce back message. I am running qmail-1.03   Regards Manny