I'm currently developing a new store with Drupal Commerce. However I'm stuck at setting up the shipping costs. I hope someone can point me in the right direct on how to calculate shipping costs based on taxonomy terms.

I'm trying to accomplish the following. Our product display nodes have taxonomy terms to categorize them in categories (we have no taxonomy term on the product itself). All products inside a category have the same shipping costs. And if there are multiple products in the cart for different categories than only the highest shipping costs should be calculated.

E.g.
There are 2 products in the shopping cart. One product is from a category where the shipping costs are $5,- and one product is from a category where the shipping costs are $7,50. The shipping costs for the total shopping cart should in this case be $7,50.

How can I get the taxonomy terms from the display node in Rules to calculate the correct shipping costs? And how can I make sure that only the highest shipping costs will be calculated?

I hope someone can point me in the right direction to accomplish this functionality. Thanks in advance!