[Exim] possibly OT: SMTP AUTH/SSL question

We run a group of SMTP machines with round robin `load balancing' which
people point their clients at.

One of the things I would like when launching SMTP AUTH+SSL is that people
have very little or nothing to change, their client and remote server do
it all.. _but_ since SSL certs are normally tied to a specific machine,
how do I have a simple single name in the DNS for them to point their
client to?

I keeping hearing about `domain certs' but I don't know if this would be
the solution (currently I have a single exim box with a self signed cert).

Thanks very much.

--
Alan Thew
FAX: +44 151 794 4442