Nick gave the example,
| > Reply-to: listname@listdomain, email@example.com
| Having [mutiple addresses in] Reply-To is a Good ... and Damned Useful
It seems to me, though, that the list membership would be better served with
Reply-To: firstname.lastname@example.org, email@example.com
because the MUAs with which I'm familiar make it anywhere from slightly easier
to far easier for the respondent to remove addresses from the right of the
reply's To: than from the left.