Advanced filtering for portfolio items

Hello,

I am trying to find a way to filter the portfolio items in a different way: currently, I have 3 parent categories, all of which have about 8-10 subcategories. The 3 parent categories only there to “classify” the subcategories (e.g. every item is attributed to a year, a composer, and a director), i.e. the items are only assigned to the subcategories.

How can I filter so that, on the same page, people could filter by year, composer or director? For now, all the subcatogeries appear in alphabetical order and are mixed up.

The ideal would be the following:
Year: 2010, 2011, 2012, 2013 etc.
Composer: Bartok, Beethoven, Donizetti, Mozart, Rameau, Poulenc etc.
Director: Pierre Audi, Stéphane Braunschweig, Eric Lacascade, Jacques Osinski, Olivier Py

The directors pose an additional problem: they start with a first name, while I would need to classify them by the family name (which is achievable by changing the category’s id).

So I would need to filter by: parent category, and then by alphabetical order of the category id. And is it possible that the parent category would show at the beginning of each line?

Sorry for the long question and thanks for your help!