I suggest reading the rest of these comments and updating the description further. Currently it's dificult to understand that you're looking to break a large array of 6+ people into the seperate floors they are on.

I can see why you did this. The question was a little misleading when it asked for "all" of the different ways you know how.

It would be useful to be able to request a correction or change from the original kata author. I've run across several now that have had incorrect directions. This usually requires me to read the details in order to determine what I might have missed.

This is absolutly correct. I had to change undefined to null in order to pass the tests. It should be corrected.