Splitting mailbox with formail??

Hi,

I have a huge mailbox of email from the Procmail mailing list
and the SmartList mailing list. How can I use formail to split this 
into two mailboxes, one of Procmail mailing list only email and one of 
SmartList only mailing list email.

Thanks!

--Paul T. 

-- 
Windows98 (noun): 32 bit extensions and a graphical shell for a 16 bit
patch to an 8 bit operating system originally coded for a 4 bit
microprocessor, written by a 2 bit company, that can't stand 1 bit of
competition.