title: Multiple exclude values in SELECT-OPTIONS
body: <pre><code>selection-screen begin of block b4 with frame title text-b04.
  select-options: s_matkl for t023-matkl default 'Z310'.
  selection-screen end of block b4.
  </code></pre>
  <p>I have to create a new initial selection for the material group and set as default view one with excluded mat groups <code>Z310</code> and <code>Z320</code>. However, when needed, the user should be able to include <code>Z320</code></p>
  <pre><code>INITIALIZATION.
  s_matkl-sign = 'E'.
  s_matkl-option = 'EQ'.
  s_matkl-high = 'Z310'.
  s_matkl-low ='Z320'.
  MODIFY s_matkl.
  </code></pre>
  <p>I tried the above its not working.Any suggestions on how I can do this?
  Thanks in advance!</p>