The entity is not a member of a GST group. The branch has an independent system of accounting. A GST group effectively operates as a distinct entity for GST purposes. GST is payable on transactions between GST branches. Although each branch would complete its own periodic BAS, the parent entity retains the responsibility to ensure that this is done.
Legal liability remains with the parent entity.
Branching would be advisable when producers receive funding for a project and run that production through their existing company, rather than establish a separate company for the project. This is often the case with low budget drama and documentary. Generally the film production takes place in a different location from the normal activities of the production company. A branch may be registered at any time. It does not have to be at the time that the 'parent' registers.