It depends where you are in relation to the speakers, how loud your voice request is, and which speaker Alexa will determine to be the closest device based on those factors.

You can always disable the microphone if you don’t want Alexa to respond on certain speakers.

I have an unusual situation where a pair of MOVE’s, a ROAM, and a DOT are within six feet of each other. Alexa is very aware of which unit is closest to me as I move around the room. In the case of the MOVE’s, I only enable the microphone that is most distant from the units..

I don’t think that you would have any issues if the units are in different rooms.