title: Borders between column groups in matrix
body: <p>I have a tablix in SSRS with multiple column groupings. I'd like to put a border between the major grouping that is different than the minor grouping.</p>
  
  <p>For example:</p>
  
  <pre><code>            -----------------------------------------------------
             | Group 1                  | Group 2                  |
              -----------------------------------------------------
             | Sub 1    Sub 2    Sub 3  | Sub 1    Sub 2    Sub 3  |
              -----------------------------------------------------
  Row 1      |    10       20       30  |    10       20       30  |
  Row 2      |    40       50       60  |    40       50       60  |
              -----------------------------------------------------
  </code></pre>
  
  <p>Above, there is only a border around the major group (Group 1, 2) and not around the minor groups (sub 1, 2, 3)</p>
  
  <p>Any recommendations on how I might accomplish this are appreciated.</p>