SV: "Redirecting" all, but two, domains.

[Jan Johansson]

>    main.cf:
>       relay_domains = example.com
>       relay_transport = relay:[mail.example.com]
>       default_transport = smtp:[127.0.0.1]:10035
>       smtpd_restriction_classes = redirect_all
>
>       retable = pcre:${config_directory}/
>       redirect_all = check_client_access ${retable}redirect_all.re
>
>    redirect_all.re:
>       /^/     REDIRECT b...@example.com
>
>    master.cf
>       127.0.0.1:10035 inet n  -       n       -       -       smtpd
>           -o smtpd_data_restrictions=redirect_all
>

I think I follow this... But what if the two relay domains were to have 
different MX'es?

Thank you.