Is there any way to auto populate an item category?

[#1]

I use my online shop to sell consigned dance costumes. I have requests for ways to search for items that have a specific amount or more, is there any way i can do that? For example i have a group of 4 looking for the same costume. If they were to search my store, they would have to check each listing individually for the amount we have in inventory. They would rather be able to use a search filter or an item category to only see items that have 4 or more. If there any way to do that aside from manually monitoring and creating item categories?