Limit pre-orders for products, not for individual variants

Hi! 

My company makes women's underwear and bras in-house. 

Let's say we have enough material to make 1000 units. My customers can pre-order any size variant they want, and I will make the item. 

I can make 1000 bras. Customers might order 999 bras in size 32C and only 1 bra in size 36A. I don't care what arrangement of sizes it is, as long as I don't exceed selling 1000 units. 

Pre-order app allows me to limit how many pre-orders I allow per variant. It would be better for my business, if we could limit a total number of pre-orders per product. 
This might help explain: https://prnt.sc/pqnwpb 

Thanks!