You can put airspy_adsb on a different port and set receiver-type relay, receiver-host localhost, receiver-port <whatever the airspy port is> in your piaware config. This will end up running dump1090-fa in --net-only mode, and run a beast-splitter to feed data from airspy_adsb to dump1090-fa. Skyview is then provided by dump1090-fa.
This is a special case of “get receiver data from somewhere else”, which is what the “relay” setting does.