a common url and page for different posts

I need to have a common page for different post. like:

http://www.example.com/post-slug/rating

here ‘rating’ will be common for different post. for example:

http://www.example.com/abc-def/rating will display ‘abc-def’s rating details and

http://www.example.com/gef-ijk/rating will display ‘gef-ijk’s rating details and so on.

I don’t know what to name this functionality or how to achieve it.

Would you please share some ideas with me?