exim4: fallback smart hosts

[Jonas Meurer <jonas@freesources.org>]

Hello,

Is it possible to configure a fallback smart host in exim4? I found
information about setting fallback hosts in case that delivery failed,
but that's not really what I am searching for.

My exim4 mta uses a smart host (with SMTP AUTH) for sending remote mail,
and I would like to configure one or more fallback smart hosts in case
that the primary smart host that I currently use is not available.

Unfortunately the debconf exim4-config configuration facility doesn't
give options to configure one or more fallback smart hosts, so I'm
unsure about whether that is possible at all.

greetings,
 jonas