[Exim] exim and multiple smarthosts

hi *

i've a problem with exim: i have to use multiple smarthosts, chosen by
from-@

i used this construct:

smart_route:
  driver = domainlist
  transport = remote_smtp
   route_list = "* \"\
                 ${if
match{$header_from:}{\\@account_a\\.*\\$}{mail.account_a.org} \

${if_match{$header_from:}{\\@account_b\\.*\\$}{mail.account_b.org} \
                 ${if
match{$header_from:}{\\@account_c\\.*\\$}{mail.account_c.org} \
                 {mail.account_d.org}}\" bydns_a"

if i use this construct, exim says, he failed to expand this construct,
because of a "syntax error in "else" substring"

anyone a idea for me?

frank