Create a copy of the filter value and name it differently, something like adding a ' . ' after name. ex: Sales.
Use the new value (copy) as filter and also duplicate the sheets of 1st dashboard and use them for new Dashboard.
Running into this same problem. Would like to not have to duplicate a sheet.
Hi Jon - If you are attempting to use one filter to control many worksheets from different data sources you can use Actions to filter using a sheet. Tableau 10 will allow you to filter across all data sources.