Custom hopper slot nbt

Currently with a lot of commands and a custom resourcepack, you can make custom GUI using the inventory of a chest/barrel, and placing enlarged items with CustomModelData in each slot. However, hoppers can't really be used with these custom GUI, as they take out the "GUI" items.

So my suggestion is to have an NBT tag on Block data that can override which slot the hopper takes from.

Something like:

HopperOverride:{north:11b,up:6b,bottom:17b}

Where north, south, east, west and up all direct towards a slot that the hopper can input from that face, similar to how a furnace with hoppers works.

Then the bottom option is what slot the hopper takes out of when placed underneath.

Preferably it would be that you can only input/output from those exact slots, instead of all slots between the specified and final slot.

Or perhaps have the inverse, where you can set an IgnoreSlots:[] on hoppers themselves, which would allow for multiple input/output slots