[Exim] skip outgoing spam check in router

Hello,

I have the following router in my exim configuration file:

spamcheck_router:
  no_verify
  domains = ! +local_domains
  condition = "${if and { {!def:h_X-Spam-Flag:} \
                          {!eq {$received_protocol}{spam-scanned}}} {1}{0}}"
  driver = accept
  transport = spamcheck

I'm trying to only run mail from outside my domain through SA. This doesn't seem to work with the router I have. Can anyone provide pointers on how to bypass the router for mail from inside my domain?