It's an abstraction, not genealogy. It's about raw materials and (intermediate) products that are the leafs. In packing.carton.6_bottles (index 3.***18***.2) and packing.carton.12_bottles (index 3.***18***.5) the leaves have to be unique. The names can appear in other branches. Even packing.carton.6_bottles.6_bottles (index 3.18.2.27)could exist. packing.carton.6_bottles (index 3.***22***.2) should not be possible