If you mean that you want to poll over both IPv4 and over IPv6 simultaneously, there's not a clean way to do that. You can create a second model of the device, so that you have an SNMP model that polls over IPv4, and then create an IPv6 Pingable. It's not really ideal, but it does test reachability of both. If you just have a single model for the device, it will poll using the primary network address, whatever version that is.