I have many products that have add ons or upgrades. Is there a module to handle this. Right now, I have to set attributes on the items and add the cost of the attribute but if the cost of that attribute/addon changes, I have to visit EACH product and change the price!

I would like a module will allow me to set an attribute or upgrade and if the price of that changes, all the products that have this attribute upgrade option will be modified.

Thank you