Got the idea and verbiage from here: http://www.computerperformance.co.uk/w2k3/services/DHCP_UserClasses.htm

What we are doing here is creating a custom user class, which has a different set of server options. The server class will be set via logon script and computers will retain that class on next reboot.

Step one:
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.

Step two:
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.

You may need to put the adapter into the line by:
IPCONFIG /setclassid "Local Area Connection 3" director

Release Renew, then check by ipconfig /all and ipconfig /showclassid