Hi,
We develop code snippets for such cases for our premium customer.
We will suggest you the following things:
* You can go for the premium version of our plugin & we can provide a code snippet to exclude certain shipping class products from calculating real-time rates.
* Or You can go for our shipping pro premium plugin & per product. This will suit your requirement as well.
However, you need to configure shipping rates for each product. That means there would be no real-time rates.
Let us know, if you have some query