Hello,
The first thing that comes to mind for your requirements is the Order Limits (MinMaxify) app.
I know that this will allow you to set a maximum (as well as minimum) product quantity.
From your post here, it sounds like you also want to restrict which products a customer can purchase as well as limiting the quantity of that item to one per customer?
I’m not 100% certain, but it does sound from the app store page description that this app should also be able to limit:
- Number of items for a specific product
- Number of items within a group of products
If you still face any issues then please let me know