I was looking for a "simple" solution, like a second installation of calibre to completely separate audio books. All the descriptions look rather complicated and it will be 188GBs to sort and transfer.
I have just three audio folders, books, classical and rock.music, and it is easy to find things there
For e-books I find calibre extremely practical, as I have over 1000 medical books which can be found over the tabs list easily. That is really great.
So, once again: Thank You