[exim] One e-mail address, multiple deliveries

I'm wondering if it's somehow possible to have one e-mail account and
multiple delivery destinations.

let me explain (parts of config file at the end.)

i've got an e-mail account foo@???

every incoming mail send to this e-mail adresse should be delivered
locally using local_delivery, but! it should also be forwarded to
another e-mail address user@??? using redirect

how can i accomplish this please?

i've first tried to simply put the 'unseen' option to my first router,
but then the sender will receive an 'unroutable address' error if the
second router doesn't validate (like if the address doesn't have a local
mailbox, but just gets forwarded).

any ideas?

thanks a lot in advance for your help...

yves

part of exim.conf follows:

## ROUTERS

mysql_aliases:
  driver = redirect               
  file_transport = address_file
  pipe_transport = address_pipe           
  data = ${lookup mysql{SELECT dtAlias FROM tblAlias WHERE ....

mysql_user:
driver = accept
condition = ${if eq{} {${lookup mysql {SELECT dtUser FROM tblUser
WHERE ....
transport = local_delivery

## TRANSPORTS

local_delivery:
  driver = appendfile
  maildir_tag = ,S=$message_size
  directory = /var/spool/virtual_mail/$domain/$local_part          
  create_directory
  delivery_date_add
  envelope_to_add        
  return_path_add
  maildir_format
  user = mail
  group = mail    
  mode = 0660
  no_mode_fail_narrower
  use_fcntl_lock                   
  use_lockfile
  directory_mode = 0770