Hermione was in North, and they and South were charged with getting into the Death Eater house where the documents were, neutralising the enemy within, and getting out with the documents. East and West had to keep the house contained; there were other residences in the town that billeted members of the swelling ranks of the Death Eaters, and as soon as the town was breached Caterwaul charms would alert the Death Eaters to the intruders.