[exim] question about clustering exim

Hi,

I'm a very new user. I've already have exim 4.69 configured for local users. What I want to do is configure a cluster of exims..for a test bed. Basically I want to put half the users on one machine, half on the other, using one domain name. Are there any example config files to show me how to do this, or something close?

Thanks!
Don