stackble attributes

i wanna make stackble item buffs with attributes such as if you have a special item in your inventory it gives you +1 damage when if you have 2 of those it gives you another +1 and so on, but from what i see if you make an item have an attribute modifier it doesnt matter if you have one of them or a 100 itll still give you the modifer only once, is there a way to change that or go around it?