External forwards and dovecot-lda

[Rod K]

I'm currently configuring a new server using Postfix/Dovecot.  My 
previous experience is with Courier and I've been using Postfix's 
virtual lda.  I want to start using dovecot-lda.

Here's the issue, I have several external forwards such as 
joeb...@internal.tld > joeb...@external.tld where external.tld is NOT 
hosted by me obviously.  Of course, I also have internal 
aliases/forwards as well (janeb...@internal.tld > 
someonee...@internal.tld and joe...@internal.tld > 
joe...@anotherinternal.tld)  Utilizing postfix virtual lda this wasn't 
an issue, both internal and external forwards/aliases worked fine.

If I understand Dovecot lda correctly, I need to rewrite internal 
forwards/aliases before sending to Dovecot AND I need to have external 
forwards sent to Postfix virtual and this is the part I'm not clear on.  
Unless I've missed something there doesn't seem to be a way to define 
transport on a per address basis.  Or am I totally thinking about this 
the wrong way?

Thanks