I have default post type "post" and created custom post type "restaurants". I have categories (not taxonomy): cat1 and cat2. I want to work with same categories on both post types and I don't want to create taxonomy for custom post type. If I visit site/cat1 or site/cat2 I will see posts which contain these categories. I need to make archive pages for cpt like this: site/restaurants/cat1 site/restaurants/cat2

I can easily do that by adding rewrite rules. But I think this is not a perfect way: for example, sitemap.xml will not contain these pages.

Do you know the way to implement it correctly?