Restrict categories to a custom post type

In the WP-Admin when creating a post or a custom post type I want to restrict certain categories to a custom post type. For example, Posts will only be able to select Category A and B. And custom post type A will only be able to select Category C and D.

Would I have to write some code to hook into somewhere or is there a function built-in to the framework?

Thanks in advance.

I think the best way to do this is to make a category (or taxonomy ) for a specific post type…

please see this link… http://net.tutsplus.com/tutorials/wordpress/introducing-wordpress-3-custom-taxonomies/