title: WordPress Other post categories redirect to primary category
body: <p>I have posts with <em>n</em> categories, but one is primary.</p>
  
  <p>Example categories: test(primary), test1, test2, test3</p>
  
  <p>One post has <em>n</em> links for each other categories. This is bad for SEO. The example below:</p>
  
  <ul>
  <li>www.domain.net/test/post-name</li>
  <li>www.domain.net/test1/post-name</li>
  <li>etc.</li>
  </ul>
  
  <p>I want the post to be displayed only in the link with the primary category.</p>
  
  <p>www.domain.net/test/post-name</p>
  
  <p>How can I achieve this?</p>