Make “Out of Stock Threshold” filterable or customisable per product

We have a client who would like to have a different “Out of stock threshold” for some products.

This is different from the “Low stock threshold” setting which just notifies the site administrator, it doesn’t show the product as out of stock on the web site and products can still be purchased.

There is a new requirement to set the “Out of Stock” level to be different for products in different categories but currently there is no field for that at a product level and there does not seem to be a hook or filter that would allow us to write something to do that.

Is there someone who can help me?