[Xymon] XymonPSclient define hostname in config?

Hi, I'm installing the XymonPSclient on a number of machines that were built by someone else, and they all have the same hostname.? What line can I add to the xymonclient_config.xml file to define a different hostname for each client?? I've looked in the instruction doc and can't find that it's an option.

-- Kris Springer