Remove sequential number from permalinks

Question

I'm organizing some custom post types by taxonomy so that my URLs would look like

/small-groups/spring-2015/date-your-mate
/small-groups/fall-2015/date-your-mate

The spring-2015 and fall-2015 are the slugs of my custom taxonomy.

However, when Wordpress generates the permalinks for the 2nd "Date Your Mate" it comes back with (notice the -2)

/small-groups/fall-2015/date-your-mate-2

Is there an option that I can use to turn that off so that the system queries with in the taxonomy and not need any sequential suffix (the -2 part)?

I'm guessing that this can be changed by hooking into the wp_unique_post_slug filter, but I'm not sure how

Answer 1

I don't know if you can use pages for your purpose, but as in the comments in wp-includes/post.php line 3701 (in the wp_unique_post_slug function), you can use identical slugs for pages in different trees:

/*
 * Page slugs must be unique within their own trees. Pages are in a separate
 * namespace than posts so page slugs are allowed to overlap post slugs.
 */

There seems to have been a plugin for what you want a few years ago, but it has disappeared since.

Right now I don't see a way to do it without getting at the core code.