Just say Alexa play Rolling Stones in kitchen and it’ll play to whatever echo is set as kitchen from any echo device.

Just did an Origin acoustics valet amplifier with 4 dots plugged in locally, and he has half a dozen round the house. The 4 in the valet amp are named kitchen, dining room, bedroom and study. At any dot in the house he just says play bob Dylan to any of the room names and it plays, you can change volume etc fine from any dot.