[exim] localdomains file for non-authenticated, dns for rest

begin routers

lookuphost:
    driver = dnslookup
    #domains = ! +local_domains
    ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
    transport = remote_smtp
    self = pass

I would like to change this so that emails from authenticated smtp
users always use dns for loockup and emails from non-authenticated
(remote mail servers) always use local_domains list. Anyone has idea
how to do it?