Item management problem

After playing 50hrs, there’s one thing bothers me a lot: the item management.

Every item group qty is 20 pcs, after using some amount out of two or more different groups of the same kind of item, for example, there will be 12 pcs of food A as group 1, and 5 pcs of food A as ground 2, there’s no way to unit two groups together in Item. The only way to put them together is to open one chest, move them in and out.

Please make key in Item to put things in order.
Many thanks.