Task sharing among four plus one

For harmony reasons, tasks have to be shared explicitly, i.e. it should be clear to all members of the family who has what kind of tasks to perform in the managing of the household. You can use a round robin system, that switches responsibilities each week, month, ... This should be a fairly good system for sharing labour-intense low-expertise tasks. But exactly for those tasks, external suppliers could be attracted -- given the fact that five people will bring in more than enough money to subcontract. For knowledge-intense tasks, however, it seems better to assign a small set of main expertise areas to each of the family members. Each of them builds expertise and is allowed to take decisions based on a low frequency of consultations of each others desires. E.g. one person could be responsible for health and food, giving this person the responsibility over the menu -- but only after this person has consulted all the menu and diet desires of all the others.