The Oceanis group acquires Medilab, a network of laboratories located in three countries. Oceanis has two operating segments; the expected synergies concern only the Health segment, where management monitors performance, goodwill included, at the level of two regional hubs, each grouping several CGUs. The controller proposes either to test the goodwill at the level of the whole group, or to create CGU-by-CGU reporting, aligned with the country-level tracking performed for IAS 21. Write a memo justifying the level at which goodwill is allocated.