How to forward all email except...

[Gerald Brandt]

Hi,

I have kolab configured for domain example.com.  So a user will get 
email for user at example.com.

I'd like to change is so any user at example.com gets sent to an 
external host, and any user at mail.example.com is delivered locally.

I'm doing this for migration purposes.  I have an Exchange server that 
has been running for years.  As users are added to Kolab, I tell the 
exchange server to forward emails to user at mail.example.com. This works 
like a charm as long as each user has a secondary email that matches.

If a user on Kolab sends email to a user on Exchnage, I start getting 
issues.  The email bounces because the Kolab user doesn't exist on the 
domain.  So, I want to send ALL email to exchange, and then for migrated 
users, it can forward back to mail.example.com

Once all users are migrated, I need to chnage it back to except for the 
domain.

Is this possible?

Thanks,
Gerald