Inventory placeholders

I would like to have ability to lock inventory slots so they can only contain specific items.

For example if I wanted a chest to have only diamods on top row, I could lock those inventory slots so when I take out all diamonds, they would leave placeholders so no other items than diamonds could occupy those slots.

This would make it alot easier to keep chests organized.

Right now you can accomplish this by leaving one item on an inventory slot, but it's tedious having to constantly manage inventory and remembering to leave placeholders.

This wouldn't be too overpowered, but it would make redstone based item sorters obsolete/simpler, which may or may not be a good thing.