Ignoring bad addresses instead of aborting

Is there any way to get exim to error to the sender rather than abort
completely upon encountering a bad address?

We have several hundered mailing lists here that I'm attempting to convert
over to exim. This has meant me going in and cleaning out bad addresses
that the list managers did not realize were bad. Because of the abort
nature of exim, their list stops working when they add a bad address to it
(something like "bozo@bozoplace@???" or "My Name").

No matter how much I tell them to clean their list it still happens. It is
the old sysadmin problem of how much can you expect your users to do? As
little as possible.