This article explains how to set up a smart home group with Alexa. It also includes information on how to edit the smart home group and how to delete the group.
How to set up a group | Smart Home | Amazon Alexa
As you add more and more smart home devices that work with the Amazon Echo, it can get tricky to remember what you named each device. Worse yet, if you want to control multiple devices in one room, you have to say, “Alexa, do this. Alexa, do that. Alexa, do something else.” The good news is that you can create smart home groups for Alexa that can do anything. And it only takes a few minutes to set up.
Once you have an Echo and smart home devices, it’s easy to create a smart home group. You can manage everything through the Alexa app on your mobile device.
Open the Alexa app on your mobile device.