Você pode dar uma olhada nisso: lifewithqmail.org/lwq.html#dot-forward
e isto: greens.org/about/software/qmail/man/man5/dot-qmail.html
THE QMAIL FILE To change qmail-local's behavior, set up a .qmail file in your home directory.
.qmail contains one or more lines. Each line is a delivery instruction. qmail-local follows each instruction in turn. There are five types of delivery instructions: (1) comment; (2) program; (3) forward; (4) mbox; (5) maildir. (3) A forward line begins with an ampersand: &[email protected] qmail-local takes the rest of the line as a mail address; it uses qmail-queue to forward the message to that address. The address must contain a fully qualified domain name; it must not contain extra spaces, angle brackets, or comments: # the following examples are WRONG &me@new &<[email protected]> & [email protected] &[email protected] (New Address) If the address begins with a letter or number, you may leave out the ampersand: [email protected] Note that qmail-local omits its new Return-Path line when forwarding messages.
Espero que isso ajude - Eu não tenho um servidor qmail à mão para testar isso primeiro.
EDIT:
Pode ser necessário usar um script para criar esses arquivos para cada usuário.