[Mailman-Users] mailman domain error

[Christopher Glanville]

Hi,
Can anyone help me. I have got 2 domains. Domain a.com and domain b.com 
and I would like to be able to write messages to either of those 
domains. I cannot work out how you do this though since my mailman 
router does not take into account anywhere the domain name, only 
$local_part (see below) So another question is since it (apparently) 
doesn't look at the $local_part why is it that a.com works but b.com 
doesn't.
The /var/log/exim4/mainlog file shows no difference between a.com and 
b.com but yet b.com doesn't arrive??

Many thanks in advance for any help on offer
de Chris G

PS my mailman router is:

mailman_router:
        driver = accept
        require_files = MAILMAN_HOME/lists/$local_part/config.pck
        local_part_suffix_optional
        local_part_suffix = -bounces : -bounces+* : \
                            -confirm+* : -join : -leave : \
                            -owner : -request : -admin
        transport = mailman_transport