Based off of the excellent work over at https://gist.github.com/jjensn/83dd60d96330bbf66e58dfae336187bf
This component allows lights to be grouped together and supports all of Home Assistant's features such as effects and color temperatures. The "child" lights can still be used as normal though as this component just forwards all calls to all of the children and uses the first active child light for the group state.
In order to use this, first copy the attached code to a file custom_components/light/grouped_light.py
in your configuration folder. Then, specify all of your grouped lights like this:
light: