You're in need of a multidimensional hash.
For any of us to begin working on this to produce the results you want, you need to provide all item id numbers, though in such a manner.
Magician Head - 2500
Enchanter Head - 2501
Rogue Head - 2502
etc.
Magician Head - 2600
Enchanter Head - 2601
etc.
As you can see, which I try to tactfully suggest, if you had/have control over the item ids and know you want to do this sort of thing from the get go (which I assume so many things are in place by now that -your- best method is through a MD hash), make an item numbering convention. Too late for that now, so, time for code.
Though we will need to know the item id's of all gear, preferably listed in the manner shown above.