title: How to combine different paths in firestore version 9
body: <p>I was using firestore version 8 and used the following code to create alternations in code:</p>
  <pre class="lang-js prettyprint-override"><code>const subQuestionRef = DB.collection('groups')
                           .doc(groupId)
                           .collection('questions')
                           .doc(questionId)
                           .collection('subQuestions')
  
  if(someCondition) {
    subQuestionRef.doc(uid).set({somthing})
  } else {
    subQuestionRef.doc(subQuestionId).set({somthingElse})
  }
  </code></pre>
  <p>I couldn't find a way to create such alternations in firestore version 9.</p>
  <p>Do you know how to create alternations in version 9?</p>