Culling items?

Does anyone know how to get the branches of a tree with a specific number of items in?

Im trying to orient the sides of voronoi cells to be able to laser cut them. I cant find out how to treat the data to do a correct layout.

As you can see in the image below, with four cells, two with four sides and two with five. I'm using a list function to get the specific side and orient it flat. How to cull the data to orient it correctly?