OK, answered my own question . . .
Just pass each JSON value to a number of Entity nodes works a treat. I assume that rather than creating a dozen of these entity nodes, I could probably add a bunch of attributes to one node and save values to the attributes. Would need to test this out though.
If anyone is interested . . .
[{"id":"efa336da266c7e7e","type":"ha-entity","z":"a3702243d82388a4","name":"Testing Sensor","server":"788d326f.ff7f4c","version":1,"debugenabled":true,"outputs":1,"entityType":"sensor","config":[{"property":"name","value":"testing sensor"},{"property":"device_class","value":"sensor"},{"property":"icon","value":""},{"property":"unit_of_measurement","value":""}],"state":"payload","stateType":"msg","attributes":[{"property":"device_id","value":"sensor.testing_sensor","valueType":"str"}],"resend":true,"outputLocation":"payload","outputLocationType":"none","inputOverride":"allow","outputOnStateChange":false,"outputPayload":"$entity().state ? \"on\": \"off\"","outputPayloadType":"jsonata","x":380,"y":180,"wires":[[]]},{"id":"788d326f.ff7f4c","type":"server","name":"Home Assistant","version":2,"addon":true,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true,"cacheJson":true,"heartbeat":false,"heartbeatInterval":30}]
Cheers,
Paul