Nice article. We have hundreds of reports with tens of agencies accessing those reports restricted to only their data. My solution to this was creating a stored procedure which looked up their user id from this parameter and returned their coresponding agency. There was an agency table with a listing of agencies and users and their user ids.

Then in the dataset that returned the report data, only the data for agency to which the user belong was returned.

This allows many users from different agencies to view the same report, but with only their data.