Allow local senders only for specific accounts?

Hi,

consider I have an alias that is used to distribute certain
mail messages, on a server that is externally reachable and
accepts mails to local accounts generally, but I don’t want
to accept mails to that specific account (alias really) via
the internet, only via /usr/sbin/sendmail or [::1].

Is there a way to configure this?

Thanks in advance,
//mirabilos
--
„Cool, /usr/share/doc/mksh/examples/uhr.gz ist ja ein Grund,
mksh auf jedem System zu installieren.“
-- XTaran auf der OpenRheinRuhr, ganz begeistert
(EN: “[…]uhr.gz is a reason to install mksh on every system.”)