there is no solution to these problems that doesn't involve some
changes in MUA behavior. the question is: which changes give the most
benefit for the least transition pain?
I think the first thing you need is a third way of replying -
"Reply-To-List" which, as Bruce had told us, some MUAs already provide.
not that I entirely dismiss this idea, but I do have to wonder -
if a message is sent to multiple lists (or in general multiple recipients),
why should a reply-to-list go to only one of those lists/recipients?
Keith