You need to find out how you are doing host name resolution, if simply using the var/adm/hosts file, your users computers will be listed with their IP address (if using static IP of course), you may of course be using DNS, NIS for exaple
If using DHCP, your users computers will get a different IP address every time they bootup, but at any one time, the dynamically created arp table will list the IP address and corresponding MAC addres of any device communicating on the network with the server. If you have a network tool such as NNM, you could find the location of a MAC address.
If this doesn't help, tell us what you are trying to achieve, there may ber another way of finding the answer.
Clare