I have a Custom Post Type called Pricebooks. I then have a custom taxonomy for Pricebooks called Zip Codes. Within that taxonomy the terms are the actual zip codes. I want to limit a Zip Code (the tax TERM) to be used only one time across ALL Pricebooks. So a Pricebook can have multiple Zip Code Terms but a Zip Code Term can only be used on one Pricebook.
I've done some searching and found nothing that fits the bill. I'm open to other solutions as well like using custom fields, etc. Thanks.