Sure.
So the
dhcp-option=6,Pi-holeIP,SecondaryDNSIP
Woyld look like this:
dhcp-option=6,192.168.1.2,8.8.8.8
Assuming pi has 192.168.1.2 ip. Replace with what you have.
8.8.8.8 is the google dns
So if you use your pi as dhcp server, it will push those ips as primary and secondary ips.