You can create groups of artificial lights in a building model. For example, you may want to create groups for functional areas of a building, such as exterior lights, kitchen lights, hallway lights, and so on. Light groups can include one or more lighting fixtures of multiple types.
When you render an image, you can use light groups to turn on or off entire sets of lights, rather than controlling lighting fixtures individually. You can also use light groups to control dimming of lights in a rendered image.
Light groups are available in all relevant areas of Revit. However, settings to dim or turn on or off light groups (or individual lighting fixtures) apply to individual 3D views only.
Example
Task lights are turned on; pendant lights are turned off.
Pendant lights are turned on; task lights are turned off.