- Leave the attributes separate and then add a 'validation' on the product that will stop the customer from choosing an option in BOTH of those attributes (it will stop them and give a message like "you have chosen two different materials/colors. Please unselect one of them") so then the sections adding together will be no problem because they can't mess it up and choose 2 options.
- If you have two attributes, for example granite and marble, leave all the granite and marble options inside the same attribute (maybe called something like color options or whatever you want) and then they can be separated by headers. So they just drop down that ONE color option and choose out of the granite or marble options. Then you only have one attribute and one variable to worry about for your pricing formula. The picture below shows option 2 - you can separate each type of attribute by a header but still leave it in the same drop down menu.
