[exim] Configuring exim to use eth0:n for some domains

Hi,

How do I configure exim to use:

    eth0:1 for domains on /etc/domainsoneth0_1 file,
    eth0:2 for domains on /etc/domainsoneth0_2 file,
    eth0:3 for domains on /etc/domainsoneth0_3 file,
    ...
    eth0 for domains not listed in any of those files above

Exim everytime defaults to eth0 now..

Awaiting your answers.
--
SubZero