Subscription filters?

["Williams, Stuart" <Stuart-HPLB_Williams @ hplb . hpl . hp . com>]

Is there a clean way to automatically screen subscription requests
on an open list?

I am running a majordomo for some internal mailing lists and want
to ensure that subscribers have e-mail addressed that are local 
to my organisation. I've added the following lines to the 
'valid_addr' routine in 'majordomo.pl'

    if ( !/\.hp\.com$/i && !/\@hp\.com$/i) {
        &main'abort("HOSTILE ADDRESS (non HP domain address) $addr"); #'
        return undef;
    }

It seems to work fine, but it would be nice not to have 'hacked'
'majordomo.pl' to do this. Is there a better way?

Thanks

Stuart Williams