title: Filter values within a group, but return all values (records) for all other groups
body: <p>I have my data in this format. I would like to use dplyr to select values from Group 'b' greater than 5, but select all values from all other groups</p>
  
  <pre><code>Group   Value
  a   3
  a   4
  a   8
  a   3
  b   3
  b   8
  b   7
  b   9
  c   2
  c   3
  c   9
  c   8
  </code></pre>
  
  <p>so final table should look like this:</p>
  
  <pre><code>Group   Value
  a   3
  a   4
  a   8
  a   3
  b   3
  c   2
  c   3
  c   9
  c   8
  </code></pre>