[Exim] Smarthost only when direct send fails

Hello,

I've been trying to figure this out, but i haven't gotten too far. I'm
hoping someone here can point me in the right direction.

Basically, I prefer to run exim on my own machine. While this works well
for the majority of cases, occasionally i will need to send mail to
someone in a domain which considers people like me not worth talking to.
While i don't mind so much either saying "if they want to discriminate
against me because my mailserver isn't run by some big organization,
screw them" or telnetting to my ISP's smtp port, my fiance does.

So, my plan is to send as normal, and if the remote server responds with
an error then let my ISP deal with them. Is this possible?


Thanks