Custom freight groups in magento - Based on product cat.

I need a series for custom freight groups / levels based on product categories in a magento webshop. System should work like this: Product A, Shipping cost X Product B, Shipping cost Y If user purchase product A, then shipping cost is X. If user purchase product B then shipping cost is Y. If user purchase both A and B, then highest shipping cost ONLY (example Y) is billed. Prompt communication with Skype/GTalk text chat required. If you have read and understand this project type dd-wrt in PM and init.d in public message field.