[Dovecot] local users + virtual domains

[Micha Silver]

I'm redesigning our mail server which holds several hundred mailboxes - 
most are local system users and some are virtual domains that we host. I 
understand that the 1.0x stable release allows for multiple auth 
mechinisms, so that I could use both PAM for local users and a 
passwd-file for the virtuals. If I want to stick with 0.99x can I mix 
and match in a single passwd-file the username/passwd for both local and 
virtual users?
In dovecot.conf I'd have something like:
default_mail_env = maildir:%h/Maildir
auth-userdb = /etc/dovecot/passwd-file
auth-passdb = /etc/dovecot/passwd-file

then in passwd-file I'd enter:
# local users
localuser1:<passwd>:501:501:::::
localuser2:<passwd>:502:502:::::
...
#virtual domains
virt1 at example1.com:<passwd>:5001:5001::/var/vmail/%d/%u:/bin/false::INBOX=/var/vmail/%d/%u/Maildir
postmaster at example1.com:<passwd>:5001:5001::/var/vmail/%d/%u:/bin/false::INBOX=/var/vmail/%d/%u/Maildir
virt1 at example2.com:<passwd>:5001:5001::/var/vmail/%d/%u:/bin/false::INBOX=/var/vmail/%d/%u/Maildir
postmaster at example2.com:<passwd>:5001:5001::/var/vmail/%d/%u:/bin/false::INBOX=/var/vmail/%d/%u/Maildir
...

Would this combination work?
 
Thanks,
Micha