As you noticed, it will unfortunately be hard to implement Alexa voice command room awareness going forward unless the lastVoiceCommand channel gets fixed. This is the only way to my knowledge to determine the Echo device you are interacting with allowing different actions to run depending on the location.
Below is an example that I would have recommended using that channel.
You should monitor the thread below as there may be some good news on reinstating the lastVoiceCommand channel.
