Decomposition Tree Problem - building staff distribution

Hi Everyone

I have a big trouble with a making decomposition tree in PBI. 

I want to have something like that below (I know that I have a missing line in supervisor2 and supervisor3, it's only mistake) :

But, if I use decomposition tree, I have the visual like this:

I can't split split other supervisors like supervisor1.

How do I make a diagram showing the expected scheme? 

Regards