title: Exclude multiple senders in gmail filter
body: <p>I've been trying to set up a Gmail filter which should include all mail that was CC'ed to user A, but <strong>not</strong> those emails which are also addressed to user B or C (or both of them).</p>
  
  <p>In other words, I want the filter to select emails that were sent only to user A, but if it was also sent to anyone else on the team (B or C), it should not select them.</p>
  
  <p>This is what I was trying to write, but it didn't work:</p>
  
  <pre><code>A@gmail.com -{B@gmail.com or C@gmail.com}
  </code></pre>