Attributes and stock control (rings)

[midiman]

Hello!

I'm usin Prestashop 1.4 to create a jewellery shop, and I've got a problem to show the ring sizes. We make rings in a default size (14), and when a customer orders one ring of another size there are 2 options: if size is 3 points above or below the default one, we just ajust its size. If size is smaller o greater than that, we have to make a custom ring, cause it can't be adjusted. The problem is that if we create an attribute for each size, it's imposible to control stock movements, cause sizes 11, 12, 13 ,14, 15 16 and 17 are the same ring, but each one has its own stock in Prestashop... I've tried to create an attribute with all that sizes together, but then all of them are showed in shopping cart and I don't know wich one the customer is asking for...
So the question is if it would be possible to develop a module to solve this problem without touching Prestashop's core. If it wasn't, wich files should I modify in prestashop 1.4 to solve my problem?
I've got some php programming sikills, but I need some orientation on which would be the best way to solve this problem...
Thanks and sorry for my terrible english

Jaime

[midiman]

I've partially solved the problem: I've write a small module that hooks in orderConfirmation and adjust the stock in all related attributes to be the same. It's not the best solution neither the most elegant one, but it works for me
The ideal solution would be that there was an option when you create a new attributte group to specify if we want it to affect the stock or not...

Regards from Spain!