Ah well, are all the objects in a single model or in multiple models ? And what do you mean with "don't want to SET it" ?!?
If all occurrences are in a single model, no problem. Just read the highest occ (without incoming connections) and go from there via the connections to the next obj occs (=> recursive call with check per map if an object has already been read).
If you have multiple models with assignments, you can either go through the AssignedModels or you could try to go over the occurrences of the superior object. So if Struttura 01.02 has an occurrence in the assigned model, you could go via OccList of the object...
BR Robert