I think that is pretty much what is already half set up. Except it isn't all the way there....Need to look into how it really works but I want to see if its able to define some kind of templates for the different trader types and have them set specific items or items groups on a higher rarity or lower one.
So you could for example set it so a bookseller only sells book items etc.
I'd like to either set an item group (BOOK_ITEM_TYPE/MAP_ITEM_TYPE) for a certain trader type and/or all items with a a certain attribute (itm.indian/itm.sneaky).