Is it possible to add the amount of a product as you create an asset ?

I already figured out that you can attach an excel list for example to the asset but it would be way better if I could put the amount right in the asset and this would change automaticly. For example if I have an "in store" product asset and I create a relationship for that asset with a user, it would be great if it works that one product changes to "in use" but the others (for example 6) stay "in store".

Is something like that possible ?