Stop the autoresponder sending to lists and forwards

As an email user, I'd like the auto response feature to ignore mails delivered via lists and forwarding, so that users do not have their personal email or vacation plans exposed.

The autoresponder currently responds to too many messages, including mailing lists and mail accounts that are forwarded. It makes little sense to send a vacation message to a mailing list, and can be a major source of annoyance. Emails that are sent to a generic "service', 'sales', 'accounts' group do not want to see vacation notices from the members of those groups, and do not want their personal email accounts exposed.