title: select first two characters of values in a concatenated string
body: <p>I am trying to create a formula field that checks a string that is a series of concatenated values separated by a comma.  I want to check the first two characters of each comma separated value in the string.  For example, the string pattern could be: abcd,efgh,ijkl,mnop,qrst,uvwx</p>
  
  <p>In my formula I'd like to check if the first two characters are 'ab','ef'</p>
  
  <p>If so, I would return true, else false.</p>
  
  <p>Thanks.</p>