tradfri: Two controllers per room now possible

For the longest time the tradfri gateway was unstable and had to be rebooted quite frequently. Hopefully the new update is going to solve this.

And it brought one function that I like which is that you can have 2 controller per room. 

I do not understand why you cannot use and build any controller scenario, must have something to do with the protocol?

Use Case:

Control multiple light bulbs via motion controller, on/off switch and dimmer.