Redirect mail router rule

Hi there, I'm just wondering what I am doing wrong

I have a router rule to redirect mail arriving at one CGP but it needs 
to be redirected internally to another,

The rule I have is this, TBH I rarely use rules so I'm not sure what 
I'm doing :

mail.xxx.com = [192.168.1.244] ; explicitly relay to the IP address

This is what I see in the Logs:
00:00:13.00 4 SMTP-44331(spawtz.com) resolving 'mail.xxx.com'
00:00:13.00 4 SMTP-44331(spawtz.com) connecting to [185.43.xxx.xxx]
00:00:34.00 3 SMTP-44331(spawtz.com) failed to connect to 
mail.spawtz.com [185.43.xxx.xxx:25]. Error Code=no response

Which is correct as that's the external IP and my firewall won't do 
Out and In, hence why I need route to the internal IP..

Anyone able to tell me what I'm doing wrong please?

Thanks in advance....

#############################################################
This message is sent to you because you are subscribed to
  the mailing list <[email protected]>.
To unsubscribe, E-mail to: <[email protected]>
To switch to the DIGEST mode, E-mail to <[email protected]>
To switch to the INDEX mode, E-mail to <[email protected]>
Send administrative queries to  <[email protected]>