We are an ISP and we have several clients requesting a mailing list. Often, the names collide. No problems with email addresses, we know how to configure Postfix to have firstname.lastname@example.org and email@example.com point to different mailboxes.
But I cannot do the same with Mailman. Mailing lists are apparently unique, whatever the domain is. So, I must create info-company and info-npo and set a different host_name for each list. Not a big deal except that this name appears in messages sent and firstname.lastname@example.org is not really elegant.
I tried changing real_name. As its documentation said, it is discouraged and, indeed, it does not work (the original name still appears in messages).