I have one physical LAN, but I have several distinct groups and each should have their own subnet. What this means is each server should be able to recognize its own clients and ignore the rest. Obviously this could be done with MAC addresses, but that sort of defeats the purpose. I remember something about Vendor Arguments/Parameters/Variables/Classes and think this the way to do it, but I can't find any advice. I think the discipline is to identify each client as a member of, say "Class 1", or "Lab", or "Sales", and these classes identify the scope that the DHCP server configures for that client.
Thanks for the help,