Variable: message-alternative-emails
message-alternative-emails is a customizable variable defined in
message.el.gz.
Value
nil
Documentation
Regexp or predicate function matching alternative email addresses.
The first address in the To, Cc or From headers of the original article matching this variable is used as the From field of outgoing messages.
If a function, an email string is passed as the argument.
This variable has precedence over posting styles and anything that runs
off message-setup-hook.
Source Code
;; Defined in /usr/src/emacs/lisp/gnus/message.el.gz
(defcustom message-alternative-emails nil
"Regexp or predicate function matching alternative email addresses.
The first address in the To, Cc or From headers of the original
article matching this variable is used as the From field of
outgoing messages.
If a function, an email string is passed as the argument.
This variable has precedence over posting styles and anything that runs
off `message-setup-hook'."
:group 'message-headers
:link '(custom-manual "(message)Message Headers")
:type '(choice (const :tag "Always use primary" nil)
regexp
function))