The answer is to use ClassID as a filter for the different scope options.

To set the user class of a windows xp box:
Cmd
ipconfig /setclassid "Local Area Connection #"

To set server options follow below
User Classes - Configuration (http://www.computerperformance.co.uk/w2k3/services/DHCP_UserClasses.htm)

1) Create your User Class. Right click the DHCP server option, select Define User Classes from the short cut menu.

2) Add your chosen User Class. The trick is to get rid of the dot under ASCI and add a name that you will use for this special User Class. For example, Director.

3) Remember to create the special options for example, a new Default Gateway. To do this choose the advance tab on the Options.

4) Now we switch our attention to the clients. The key is to tell the clients which User Class they belong to.

IPCONFIG /setclassid director, would be the answer in for our example.

In 'real life' I would use a logon script to set this command, your average user would not be able to remember this command.

5) Test your /setclassid with IPCONFIG / all or IPCONFIG /showclassid