Long playlist for car and occasionally play on Sonos or amplifier

[SnijSpotify]

I have a long playlist in Spotify which I play in the car, I stream the music from my iPhone to the car stereo and sometimes I use the headphones.
I like how the app remembers where it stopped when I get out of the car and it continues when I get into the car again.

Occasionally I want to send something to my Yamaha amplifier with Spotify Connect or start something on my Sonos equipment, but my iPhone then forgets where it was on the playlist.

How do I solve that?

I can think of 1 solution, a separate Spotify account for the Sonos system, but the Sonos app doesn't have access to Spotify Radio.
For the Yamaha amplifier I can't add a separate account.

Does anybody have an idea for me?