There are at least three other topics on this same thing. We can hope that Sonos will do the right thing and allow this to be possible, but at this time it has been said that it will not be possible.
https://en.community.sonos.com/wireless-speakers-228992/play-1-stereo-pair-with-sonos-one-6791376
https://en.community.sonos.com/wireless-speakers-228992/can-i-setup-a-play-1-and-a-sonos-one-as-a-stereo-pair-6791368
https://en.community.sonos.com/amazon-alexa-and-sonos-229102/pairing-a-play-1-with-the-new-sonos-one-6791476
The S in IOT stands for Security.