bobn,
1. please see reply to rkg above.
2. The actual category names don't follow the pattern I used as an example (cat1, sub1).
I typed it like that so people could understand the relationships. I thought it'd be easier to read than a 'fruit' - 'apples', 'bananas' / 'snacks' - 'crisps', 'chocolate' type layout.
Sorry for the confusion.