hi ya paul...
have a look at my ( out-of-date virtual domain mini-howto )
for configuring majordomo for your virtual domains
- i used smail to configure mail, sendmail uses virtualtables
- go to dejanews.com and search for it... ( prev postings/solutions )
>  How do I configure majordomo and sendmail so that recipients see
> the To: line as firstname.lastname@example.org, the From: line as
> email@example.com, and references to majordomo itself
> within the message as firstname.lastname@example.org ?
> [I know weferences to majordomo itself are based on the majordomo.cf
> file, but how does that handle multiple domains?]
>  How do I make this work for both otherdomain.com and
> thirddomain.com, (and any other domains we add later)?