Best Practice on using Organization Tree

Summary:

Currently we have one Organization Tree with the below structure

Enterprise (Company XYZ)

Business Unit (US XYZ)

Department (Project Expenditure / Task Owning Organizations)

DEPT XYZ 1

DEPT XYZ 2

Business Unit (UK XYZ)

Department (Project Expenditure / Task Owning Organizations)

DEPT XYZ 1 ->>>? not possible to add the same department to another node

DEPT XYZ 2 ->>? not possible to add the same department to another node

Department names are same across BUs but since we cannot add the same department names to another node (i.e UK XYZ) do we have to create another department for example adding a prefix to differentiate UK and US departments