OpenCart v3 Need multiple tax classes to be associated with each item

In OpenCart, you can currently only select one tax class to be applied per product. The issue here is that the user has an option to have the product shipped, or picked up. If they are picking it up, they need to pay taxes no matter what. I cannot set up one tax class with the logic of "Charge taxes based on the shipping address", and also "Charge taxes to anyone if they are picking it up". I currently have 2 different tax classes to handle this, and the shipping options will try to charge taxes based off of the shipping option selected. The issue is that since the "Pickup" option is not associated with the product, it does not charge taxes. If I do change the product to have the "pickup" tax class, then it drops the "shipping" tax class. How can I have it both ways?

If you want to set up a fee outside the tax system, you could do this with Shipping-Based Fee/Discount. It lets you add a new line item to the order based on the shipping choice of the customer, so you could add a fee based on state and/or postcode. If you just need a percentage fee based on state, then Simple Payment Fee would also suffice.

This would NOT be part of the tax system, so it wouldn't show up in tax reports, but it would allow you to set a tax based on the shipping choice. So if someone chose "Pickup From Store" and you wanted to add your state's tax, you could do that.

Feel free to take a look at the screenshots and demo site, and if you're interested let me know at www.getclearthinking.com/contact if you have any further questions.