SMTP from dialup

Hello postfix list

I want to configure / hack Postfix to deliver mail as follows
from a dial-up connection:

1. First try to deliver directly to the destination - this is
faster, more reliable, and less prone to bugs and buck passing.
However, it may fail with 450 or 550 "You are blacklisted".

2. If there is any error in the first step, then forward the mail
to a smarthost (i.e. the ISP's somewhat erratic SMTP relay which
is not blacklisted as a dial-up).

Is Postfix capable of doing this?

&:-)


--
I don't believe in evolution or microsoft outlook