Yup - only Sonos can link Spotify zones from the Spotify app. Until Airplay 2 comes on-line or Spotify opens up to other platforms (who knows if / when they will do this with their recent moves) Sonos is the only one to do this. Otherwise you'll need to group within the manufacturers apps.
This industry is not getting cheaper and cheaper, we're simply convincing ourselves that we have to push the cheapest option to customers. #makesonosgreatagain