DHCP and multiscopes

I was wondering if the following is possible.

Setup a DHCP server with two scopes:
192.168.1.1 – 192.168.1.126
192.168.1.129 – 192.168.1.254
both with subnet 255.255.255.128

All clients are one the same physical LAN.
Now the question.

How can I configure DHCP to give a group of clients dedicated IP addressess from the first scope and other clients dedicated addresses from the second IP scope?

Thanks in advance for your replies.