[exim] rewrite subject

Hi, i have this route rules for manage groups, and i would like rewrite the
subject of messages with the group name.
It's possible? How-to?
Thanks.

virtual_dom_groups:
  driver = redirect
  allow_fail
  senders = ${if eq{Y}{${lookup
sqlite{/home/gestionaisp/web/sqlite/sqliteDb/mail.db select g.is_public \
                                      from groups g, domains d \
                                      where d.enabled = '1' and d.domain =
'${domain}' and \
                                            d.domain_id = g.domain_id and
g.enabled = '1' and \
                                            g.name = '${local_part}'}}} \
                 {$sender_address} \
                 {${lookup
sqlite{/home/gestionaisp/web/sqlite/sqliteDb/mail.db select c.member \
                                 from group_contents c, groups g \
                                 where g.enabled = '1' and \
                                       g.id = c.group_id and \
                                       g.is_public = 'N' and \
                       c.member = '${sender_address}'}}}}

  data = ${lookup sqlite{/home/gestionaisp/web/sqlite/sqliteDb/mail.db  \
            select c.member \
            from group_contents c, groups g, domains d \
            where d.enabled     = '1'           and \
                  d.domain      = '${domain}'   and \
                  d.domain_id   = g.domain_id   and \
                  g.enabled     = '1'           and \
                  g.id          = c.group_id    and \
                  g.name        = '${local_part}'} }

local_part_suffix = -*
local_part_suffix_optional
retry_use_local_part
reply_transport = address_reply
pipe_transport = address_pipe