I need to disable all but one USPS shipping service (Parcel shipping) if any product in the cart has a certain custom product option (a checkbox) set.
I am a very good with Wordpress, but I am new to Drupal and cannot find a way to make this work.
What I've been trying is to set data comparison condition rules on each rate that I don't want to be available (Priority Shipping, etc). However, I can't seem to drill down to the products in the cart in order to check the product field value since I only have site: and commerce-order: root selectors available.
I am working with the latest version of Drupal and Commerce and USPS shipping modules.
Thanks for any help or direction!