If you search these forums you’ll find this has been raised and answered many times. It seems to be a feature that Amazon will not allow to be implemented.  Of course you could change the wake word for the kitchen device so you have a workaround, unlike those with family members called Alexa. 

I have a similar issue - with a Sonos One in one room and a Sonos Move in another.  Often both will respond to the wake word and, as they are configured to different Amazon/Spotify accounts, one will usually play exactly what we’ve requested, whilst the other might do something completely different - often resulting in a different song being played in each room. Obviously asking Alexa to stop playing (the unwanted music) can also trigger in both rooms.  So, using voice control can quickly become really annoying and we’re having to keep doors shut between rooms to reduce the impact - or just resort to using a device to request music.  Considering swapping one over to Google Assistant, however, we have Google Home and Google Home WiFi devices that will then start responding, too.