Outlook Reply All question

[Darryl]

Greetings,
We are using a mixture of Outlook 98 and Outlook 2000. We have an internal
msmail post office
for internal email.

Here is the problem:
A user crafts an email and addresses it to internet email addresses &
internal email addresses.
The message is sent successfully. The recipient gets the email. Presses
Reply-All and crafts
a response. Sends the email at which point it pukes up errors about each of
the internal
email addresses.

I have examined the headers of the sent email and it does have references to
our internal
email address. How do I elimate the addresses from the header, or for that
matter just
fix this problem ?

thanks,
Darryl