In response to "D.M.Chapman":
> Yep, hosts_randomize will help for now. I think I will hold off moving the
> main mailstore machine though. We have 3 mx machines and one is somewhat
> slower so I wouldn't want it getting one third of the traffic really.
> Cycling between the other two seems like a step back so I'll leave it
> for now.
Well, you _could_ use a route list that was expanded using embedded
perl with a random function that returned one machine each time it was
called but gave the slower machine a smaller proportion of the time.