[Dovecot] Global fields for passwd-file database

Is there a way to specify global fields for passwd-file DB? Currently interested in "home" for userdb and "allow_nets" for passworddb. The next doesn't work, of course:

passdb passwd-file { args = username_format=%n allow_nets=127.0.0.1 /etc/dovecot/dovecot.passwd.%d } userdb passwd-file { args = username_format=%n home=/var/mail/%d/%n /etc/dovecot/dovecot.passwd.%d }

-- Best regards, Sergey Urushkin