Best answer by Chris
Lets assume you have Sonos one in zone called bedroom. And you have an Echo Dot and a Play:3 in room called Kitchen.
To play music on the Sonos One you say "Alexa play Bruno Mars"
to play music on the Play:3 you say to your dot "Alexa play Bruno Mars in Kitchen"
As long as Alexa discovered your Play:3 in this case when you did discovery originally with the Sonos One - this should work right now.
All the same commands you say to Sonos One should work with the Echo dot - just always say "in kitchen" in this example afterwards.
Alexa turn it up in kitchen
Alexa pause in kitchen
Alexa play Bruno Mars on Pandora in kitchen