Price group

[quendi]

Is there a module that would add to the price of the products in a category? I'm not talking here about a group of customers. I got a question and do not know what to do with it, because the person who sent it to me described the situation like this.

 

They group the price of products in this category. This person wants to make the amount in the price range was multiplied by the number of grams (would it be jewelery shop) and gave it to the price of the item. So the upgrade price would amount only to a change in the amount of the price range.

I hope that this is as clearly described.

Regards