ure_post_edit_access_authors_list

ure_post_edit_access_authors_list filter allows to modify authors list which posts should be allowed/prohibited for editing for a current user.

add_filter('ure_post_edit_access_authors_list', 'ure_modify_authors_list', 10, 1);

function ure_modify_authors_list($authors) {
  // modify comma separated string of authors user ID as you wish here

   return $authors;
}