Postfix, local accounts and forward for domain

[ivengi]

I would like to have the possibility to run the following setup:

local accounts:
user1@domain.com
user2@domain.com

In the domain table, I've added domain.com and in the mailbox table I've added user1 and user2. This functions without problems.

If an email is received for a non existing local mailbox I want the mail to be forwarded to a different SMTP server.

In the transport table I added an entry:
domain.com smtp:[IP.OF.SMTP.SERVER]

But unfortunately all mail is now forwarded to the SMTP server and mail to user1 and user2 are not delivered on the local system.

What can I do so that postfix does "mailbox before transport" instead of "transport before mailbox"?

[thecaoticone]

I am not sure if this is what you are looking for, but from what I am understanding you want to do, this might help.

http://www.postfix.org/rewrite.html

at the bottom:
Non-existent users