How to pass a range of IPs by a specific DNS?

I'm using the Toastman 9008.6 R7000.

I know how to do with MAC address, but with range of IPs, any help?

dhcp-mac=set:altdns,XX:XX:XX:XX:XX:XX
dhcp-option=tag:altdns,option:dns-server,208.67.222.123,208.67.220.123