Inventory issues?

I sell some items in a set of 6 but if they buy two sets, they get a discount.  So I set up the item and made variants.  One is a set of 6 variant and one is a set of 12 variant with a discounted price.  For those who by a set of 12, they get two packs of 6.  So how do I set the overall inventory.  The item say has 10 sets total and if they buy a set of 12, then it cuts my stock from 10 to 8, and so on.  Is there a way to do this?

Squarespace cannot do this by itself, but there’s a Squarespace extension called Trunk Inventory that takes care of it. It’s not cheap though (from $29 per month).

21 hours ago, paul2009 said:

Squarespace cannot do this by itself, but there’s a Squarespace extension called Trunk Inventory that takes care of it. It’s not cheap though (from $29 per month).

Well that's unfortunate...