Each function had a different family that would oversee that task and now we find ourselves in the work of the gatekeepers. Remember this is King David who assigned these positions. The gatekeepers were basically sanctuary guards whose tasks included opening the doors of the temple in the morning, taking charge of the flour, wine, spices and oil for sacrifice, as well as other administrative duties that the king might require.
This clear separation of duties allowed there to be treasurers, regional officials and judges. There was a vast empire that had to be controlled and that empire needed a vast number of people who were involved in the duties to which they were assigned. We are getting a peek into the organizational structure of Israel as it took an army of people, both militarily and civilly in order to run the nation. The same is true of a church. We cannot function just as a few individuals offering a few programs and services. The whole body has to pull together.