Two options in tableau 9
first is to use action filters, create a list in a sheet of your options and then use a select filter action to filter the second datasource.
Second to use a parameter and apply this filter to both data sources.
In tableau 10 (or at least the beta i'm playing with) this is native functionality in the tool (cross datasource filters).
Refer this thread it almost had same requirement
This issue almost solved on the latest beta version of tableau.Take a look at below article,
Thanks for your link. But, currently i am working on Tableau version 9.
If it is possible in Tableau version 9 then please let me know.
Filtering across multiple data sources can be done via parameters in Tableau 9. But please remember that parameters do not dynamically updated the values. You may expect the feature of filtering across multiple data sources in Tableau 10.