title: SSRS group based on two columns
body: <p>I have a report that displays a list of duplicate accounts based on our business rules. This works when one new account is matched with other existing accounts. Where I'm having trouble is when multiple new accounts match the same existing duplicate.
  Here's an example of how it looks now, grouped by NewId:</p>
  
  <pre><code>NewID   MatchedID   FirstName   LastName    AddDate      Address        PhoneNumber
  10      10          Holly       Johnson     4/18/2013    123 1St Rd.    123 456 7890
  10      2           Hollie      Johnson     1/1/1990     123 1St Rd.    123 456 7890
  
  11      11          Holley      Johnson     4/17/2013    123 1St Rd.    123-456-7890
  11      2           Hollie      Johnson     1/1/1990     123 First Rd.  123 456 7890
  
  50      50          William     Johnson     4/17/2013    999 2nd St.    222 222 2222
  50      3           Bill        Jonson      1/2/1990     999 Second St. 222-222-2222
  </code></pre>
  
  <p>Accounts that have matches are themselves included for comparison.</p>
  
  <p>So, is there a way to group these similar accounts together without duplicates? It should look like this:</p>
  
  <pre><code>GroupID  AcctID   FirstName   LastName    AddDate      Address        PhoneNumber
  1        2        Hollie      Johnson     1/1/1990     123 First Rd.  123 456 7890
  1        10       Holly       Johnson     4/18/2013    123 1St Rd.    123 456 7890
  1        11       Holley      Johnson     4/17/2013    123 1St Rd.    123-456-7890
  2        50       William     Johnson     4/17/2013    999 2nd St.    222 222 2222
  2        3        Bill        Jonson      1/2/1990     999 Second St. 222-222-2222
  </code></pre>
  
  <p>I don't care if the grouping is done in SQL or in SSRS. It would need to reference the two ID columns, because the name, address, and phone number may be different. I also need a new GroupID assigned so that they can be grouped in the report.</p>