You could buy a Roam.

A Sonos One doesn’t have Bluetooth for audio-in purposes, or any form of external input outside of the Sonos ecosystem.

Your best option would be to use a separate Sonos product with line-input (ideally) from the TT, such as the Sonos Port (as an example), or perhaps use a Sonos speaker with a Bluetooth connection (ie. Sonos Roam) for playback/grouping with the Sonos One.

I’m not aware of any other workaround.

hi @lifareilly you may check this video that explains the options