Option 1 :

You could create a data driven subscription that selects the Branch IDs and passes them as parameters to the report.

The benefit of this approach is that your can schedule the reports to produced periodically and automatically.

OR

Option 2:

You could select the Branches into a DataReader in .Net for each row returned you can use the ReportExecutionService to generate and render a report to PDF format.

We use option 2 very sucessfully. It allows us to generate the reports when we are ready for them and we then attach each report to an email and send them to the appropriate recipient.