The ESU structure is comprised of both Geographical and Category Branches.  Members of a Geogrphical Branch can work in different parts of the ESB but actually work in the same geographical location.  Members of a Category Branch work under a common set of T&C's.

Each member of the ESU is, with few exceptions, assigned to both a Geographical and Category Branch.  These can and do change as and when members move within ESB.