There is -as far as I have been able to find- no way to assign a lightgroup to an area. In my case this means I cannot control these groups as part of a room when controlling devices with Google Assistant. As light groups are core functionality I would think this was not overlooked but there seems to be no way to assign an area.
Please add the possibility to assign an area to a light group
I am also looking for this functionality, so if it does already exist, could someone please explain how. Otherwise, I add my +1 for this function to be added.
The light can be assigned to a room inside the Google Home app. This is a valid workaround. Just to make sure you are aware. I totally agree it should ideally be possible to assign an area.