Let's say I've created two custom post types, one called post_type_author and another called post_type_book. In each of these two custom post types, I've created a non-hierarchical taxonomy for tags.
What is the best way to associate these two custom post type's taxonomies?
Also, if I wanted to link these two along with the default "post" post type, how would that be done?
What I want is to use the same non-hierarchical taxonomy "tags" for each of the three post types, so that a tag permalink called "Chicago", for example, will pull a post called "Saul Bellow" from the "post_type_author" custom post type.
It should also pull a post called "Great Chicago Landmarks" from the "post_type_book" custom post type tagged "Chicago" AND another post from the default "post" post type that was also tagged "Chicago".
Do I create two additional taxonomies and link them to the "post" post type taxonomy? Or is there a better way?
I hope this makes sense and thanks very much.