NAT only IPv4 and not IPv6 in Single Firewall Policy

I have a bunch of existing LAN->WAN IPv4 policies that use static SNAT. I want to add IPv6 source/destination to these policies but we assign public IP addresses via DHCP to our IPv6 clients and I therefore don't want NAT on those clients. Is there some way, that I'm missing, to have a single policy for IPv4 and IPv6 with different NAT options for each protocol? Do I have to use Central NAT to do that?