Restrict Inventory Slots in a Block's GUI

Hello fellow modders,

Is it possible to restrict certain inventory slots in a block's GUI from being accessed by players / only allow the player to insert certain items into these slots?

I already know about 

CustomTileEntity.canExtractItem(int, ItemStack, Direction): Boolean
CustomTileEntity.canInsertItem(int, ItemStack, Direction): Boolean

but this only works for adjacent blocks inserting into / extracting from the block's inventory. You can still insert Items into "blocked" slots by using the block's GUI. I couldn't find anything about this topic on the forum so I believe this question has not yet been asked.

Thanks in advance