[exim] I need help with routing a mail preference

Dear Exim User,



I am having a big of problem with certain task I want to accomplish..



This is the background of what I have and need to accomplish..



I have two Mail servers mx0.whatever.com and mx1.whatever.com.. I have a
queue mail server queue.whatever.com.. My two mail system are sharing
storage via GFS (SAN) so whenever the queue mail queues mail on the storage
the two mail server start sending mail immediately base on the
routing/transport regular expressions..



begin routers



dnslookup:

        driver                  = dnslookup

        domains                 = ! +local_domains

        transport               = remote_smtp

        ignore_target_hosts     = 0.0.0.0 : 127.0.0.0/8

        no_more

system_aliases:

        driver                  = redirect

        local_part_suffix       = +* : -*

        local_part_suffix_optional

        allow_fail

        allow_defer

        data                    =
${lookup{$local_part}lsearch{/etc/aliases}}

        group                   = www

#       user = exim

        file_transport          = address_file

        pipe_transport          = address_pipe

        driver                  = redirect

        check_local_user

        local_part_suffix       = +* : -*

        local_part_suffix_optional

        file                    = $home/.forward

        allow_filter

        no_verify

        no_expn

        check_ancestor

        file_transport          = address_file

        pipe_transport          = address_pipe

        reply_transport         = address_reply

        driver                  = accept

        check_local_user

#       local_part_suffix       = +* : -*

#       local_part_suffix_optional

        transport               = local_delivery

        cannot_route_message    = There is no users living here by that
name, check your naming.

begin transports



local_delivery:

        driver                  = appendfile

        file                    = /var/mail/$local_part

        delivery_date_add

        envelope_to_add

        return_path_add

        group                   = mail

        mode                    = 0660

address_pipe:

        driver                  = pipe

        return_output

address_file:

        driver                  = appendfile

        delivery_date_add

        envelope_to_add

        return_path_add

address_reply:

        driver          = autoreply

Now I need to identify mail and give it priority over one public IP over the
other for reputation purposes.. So we added an identifier to the Header of
the mail being queue base on Criteria (Ex: X-whatever-priority: 0 or
X-whatever-priority: 1)



I need using this criteria on the Header for one of two Mail Servers to send
the message since their IP will have a different priority base on the
criteria.. Like this avoiding both servers Public IP to be rated as bad by
ISP.



I have been reading online
(https://lists.exim.org/lurker/message/20130206.185440.3d550f40.pl.html)
and trying to get this done.. Can you provide me with some examples as of
how would you get this done.. ?



The Idea is when the Mailer system creates a Mail it gives a Header Priority
of 0/1 etc.. then base on that criteria I want from the Mail Server reading
from the queue to send one Mail (0) and ignore another one (1) that have a
different criteria which then the other mail will pick since the criteria
will be set for itself.. Thus sending the mail from a Public IP different
from the other, creating a different IP reputation..



Can it be done?



Thank you for all your help on this , since I have very little experience
with headers manipulation by exim.



Best Regards,



Rafael M. Más