Help w/ parameter(s)

Trying to add a parameter to filter data by production manager. Problem: the choices for the parameter are (i.e. Mark, John, John, Tony, Mark, Mark, Mark, Lee, etc). How do you make it so the choices are only (Mark, John, Tony, Lee, etc)?

Create a second data set in the report with SQL code similar to below. Then in Reporting Services parameters, set the parameter for mulit-value and the data source to the second data source you just created.

Select Distinct Production_Manager

From ManagerDatabaseTableName

Order by Production_Manager

|||Thanks for the help Chuck