To do someting like this you can use Parameters in Tableau. They can be called with URL parameters as described in this post: http://reports4u.co.uk/tableau-server-passing-parameters-url/
To filter you can then create a calculated field with that parameter in an IF statement.
Thanks Derk! It worked. It appeared to me though that report_id had to be in either Columns or Rows shelf in order for it to work as a URL parameter. So in tableau desktop I included report_id in Columns then published the workbook to tableau server. Now in the URL I was able to to use ?report_id= to pick the report to display.