Answered my own question
 
Check
To  - .*@(?!domainname)
 
Set
X-OTRS-FollowUp-ArticleType -> email-external
 
Just to verify - I am working on the basis that "email-external" refers to any email sent to or received from an external customer and "email-internal" refers to emails sent between agents within the support organisation - is this correct?
 
Adam.
 
 
Adam Knight | Test and Documentation Team Leader | Clearpace | M +44(0)782 449 2763 | T +44(0)845 456 3590 Ext 564 | www.clearpace.com
 
This e-mail and any files attached may contain privileged and/or confidential information. If you are not the intended recipient please immediately notify the sender by reply e-mail and delete the message from your system. You should not copy it or use it for any purpose nor disclose its contents to any other person.
 
 

From: Adam Knight
Sent: 05 August 2009 10:41
To: 'otrs@otrs.org'
Subject: Check whether email has been sent/copied to customer

Hi,
 
I have a rule which sets emails from my domain as X-OTRS-FollowUp-SenderType - agent
What I would like to do is check whether the email has been sent to the customer. If so then I want to set X-OTRS-FollowUp-ArticleType to email-external and if only sent to peopel within my domain then I want to set X-OTRS-FollowUp-ArticleType to email-internal
 
Has anyone successfully achieved a similar setup in OTRS?
 
Regards,

Adam 
 
Adam Knight | Test and Documentation Team Leader | Clearpace | M +44(0)782 449 2763 | T +44(0)845 456 3590 Ext 564 | www.clearpace.com
 
This e-mail and any files attached may contain privileged and/or confidential information. If you are not the intended recipient please immediately notify the sender by reply e-mail and delete the message from your system. You should not copy it or use it for any purpose nor disclose its contents to any other person.