I have a Postfix/Dovecot email server and want to allow messages from selected email senders and discard from everyone else, specific to my separate email accounts.  So Acct1 and Acct2 have different allowed sender lists.  I think Pigeonhole Sieve might be the way to go about this, but I haven't found anything about individual accounts.  I can live with domain level lists if necessary.  I know about sender_checks, but that seems to be server wide and I have multiple domains per server.  Has anyone on the distribution implemented this?