dot-qmail questions

The basic setup i have now is Qmail at home, and using fetchmail and
hotwayd or gotmail, i can download mail from four different accounts.

How can i setup a dot-qmail file to filter my messages and then move
them into different maildir boxes (for example, a maildir box for PLUG,
a maildir box for Cox-email, a maildir box for hotmail, etc.) ????