Because a link to an external domain is really just a way
of defining a link between a domain on your local GroupWise system
and a domain on another GroupWise system, the flow of messages is identical
to the flow of messages between any two GroupWise domains. For more
information about message flows between domains, choose the type
of link that you want to know more about in Message
Delivery to a Different Domain
in the GroupWise
7 Troubleshooting 3: Message Flow and Directory Structure.