This is an accepted solution.
Just to confirm, you have a select number of products on your store that you don't want to ship to four states? If so, this is where Shopify's shipping profiles feature (found in your Shipping settings) will come in handy. It will allow you to add all of your CBD products to a shipping profile that excludes the 4 states. You can view our help documentation on Shipping profiles here. Specifically the guide on creating a shipping profile.
Let me know if this helps! If there is anything else I can help you with, please let me know.