Postfix Domain forwarding question

[Christian Funke]

Hello,

I have set up a kolab server to serve mail for DOMAIN.COM, unfortunately I 
also have to provide support for a legacy domain OLDDOMAIN.COM, for which the 
users are identical and the mail for user at OLDDOMAIN.COM is to be delivered to 
user at DOMAIN.COM.  I habe realized this by modiying in 

/kolab/etc/postfix/main.cf

mydestination = DOMAIN.COM OLDDOMAIN.COM

and in 

/kolab/etc/postfix/virtual

@OLDDOMAIN.COM		@DOMAIN.COM

This setup works so far but has the drawback that any mail for @OLDDOMAIN.COM 
will be accepted whether the user exists or not and then it will be internally 
bounced. Is there a more elegant/efficient solution to solve this problem?

Many thanks in Advance,

Christian