Count Family Types in Space for Calcs

I have searched everywhere and can’t seem to find it.
I need to count lighting fixture types in each space.
I know I can do that in a Revit schedule by using “Count” but you cannot use “Count” in a formula.
Basically I need to
Fixture Type Wattage x Quantity / Area (And each room may have multiple types).


I think there’s a workaround here