title: How to restart this letter incrementation based on a condition using Google Sheets Formula?
body: <p>This formula does increment the letter, but how to make it re-start based on a condition in col A?</p>
  <pre><code>=A3&amp;&quot;-&quot;&amp;CHAR(ROWS($1:1)+64)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/Cv32d.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Cv32d.png" alt="enter image description here" /></a></p>
  <p>Here is a test sheet, in case you feel like pouring your blessing: <a href="https://docs.google.com/spreadsheets/d/1gh5w0czg2JuoA3i5wPu8_eOpC4Q4TXIRhmUrg53nKMU/edit?usp=sharing" rel="nofollow noreferrer">https://docs.google.com/spreadsheets/d/1gh5w0czg2JuoA3i5wPu8_eOpC4Q4TXIRhmUrg53nKMU/edit?usp=sharing</a></p>
  <p>Thanks a lot in advance!</p>