197677 Custom fields in phpprobid

Scenario: The category structure is as follows: Motors>Cars>Passenger... Motors>Cars>Trucks... Motors>Car Care>Cleaning Chemicals... I need to be able to create a custom fields for subcategory Cars that will be displayed/available during the auction listing for its all (end tier) subcategories (Passenger, Trucks, etc), however, it won't appear in Car Care subcategory. The parent category could be any subcategory in the tree, so if Passenger subcategory is chosen to be a parent category for custom field, all subcategories (if any exist) of Passenger will be populated with custom field.