At this time, there is no way to configure Exchange to do that. Most of
our customer feedback has been that our current configuration scheme,
which allows per-domain configuration, meets our customers' needs.
that's unfortunate. of course your customers are not the ones being harmed
(at least, not directly) when their mailers inappropriately reply to
messages from mailing lists.
the per-domain configuration serves a different purpose - that of not
disclosing your customers' absences to outsiders. that's a useful and
valuable feature for those who want to enable it. it just doesn't happen
to fix this particular problem.