The hierarchy is such that the major decisions should be made by an assembly of presidents at either level 1 or level 2, the responsibly of level 3 is restricted to their particular garden/block and as the voice of the owner at level 2 upwards.
There are a set of statutes at level 1, 2 and 3 which define the services and areas that each level is responsible for. The Level 3 has complete authority within his garden and should be that one that approves all activities that are solely confined within that level 3. for example if tiles need replacing in a communal area, is a fence needs repairs or light fitting need changing then only the level 3 presidents needs to be consulted and the authority for those expenditures would lay with him.
For the services of level 2 then ALL decisions with be made with the consultation of all the level 3 presidents within that level 2. if you will probably be familiar with the RACI matrix you could relate it as ;-
the level 2 presidents would be responsible and accountable, the level 3 consulted and the owners informed.
For all services of level 1, which is restricted to the shared infrastructure resort wide, all decisions should be made by the board of level 1 which incorporates all the level 2 presidents. The statutes of level 1 give the level 1 president pretty much absolute power but there are agreements that all presidents should be involved in the decision making process. So by the statutes the level 1 president would be responsible and accountable, the level 2 consulted and the level 2 informed. The local agreement ( called the Protocol agreement ) would change this to the level 2 presidents would be responsible, level 2 and the level 3 consulted and the owners informed.