How to prevent a select few items from going into my backpack

I have made a GUI using MCreator where I added a few input slots, its basically a backpack mod
My issue is: I have tiers of backpacks where I don't want to end up having a tier3 backpack inside a tier1 backpack or just any other type of backpack in another backpack
I'm trying to replicate how you cant put shulker boxes inside shulker boxes, but with different items.