[Exim] Fall back for certain domains

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Hi.

Can anyone help me I am not too hot on conditions syntax. What I need is to
send mails to a fallback host if they are not delivered on first attempt,
but for all domains apart from one

So like !domain1.com use fallback host.

Also as the fallback is specified on the remote_smtp transport would I add
this rule there? Or would I need a router first to send to a different
transport ??

Hope that makes sense.

Thanks
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