I don't know. There's something else you could try...
Same character, 2 inventory interfaces, 3 characters to store/swap the inventory between.
main character where you store the default inventory stuff. second character where you store the other things you mentioned. third character which you use to give all of the current active characters items to before giving transferring all of the items from the second character to the active character or vice versa. You would need to switch out which inventory interface should be visible based on the items.
Maybe there's a better solution that's less hassle, but this is just one that popped into my head, so I went with it.
