rmail-sort-by-correspondent
rmail-sort-by-correspondent is an interactive autoloaded Lisp function in `rmailsort.el
'.
(rmail-sort-by-correspondent REVERSE)
Sort messages of current Rmail buffer by other correspondent.
This uses either the "From", "Sender", "To", or
"Apparently-To" header, downcased. Uses the first header not
excluded by `mail-dont-reply-to-names'. If prefix argument
REVERSE is non-nil, sorts in reverse order.