[exim] Sending mails without SMTP authentication

Hi

I want to allow sending mail without authentication for single account.
I'm trying to not add another IP to relay_from_hosts, beacuse many
normal users send from that IP. How can I gently modify my acl.conf to
do that?

  #************************************
  acl_check_mail_submission:
  #************************************
           accept hosts            = +relay_from_hosts
           require message            = Please turn on authentication in
  your email client.
           authenticated            = *
           deny message            = Mailbox $authenticated_id is
  disable. Please contact with number xx-xxxxxx
           condition            = ${if eq \
                                           {0} \
                                           {${lookup mysql {SELECT
  active FROM mailbox \
                                                           WHERE
  username='${quote_mysql:$authenticated_id}'} \
                                           }} \
                                   }
           control                 = dkim_disable_verify
           accept