There are probably several different ways to come to a solution on this, though specifically, you cannot limit an action to only a single value of a dimension.
The possibility that comes to my mind is to have a sheet included in the dashboard that shows the details and has a filter based on a calculated field that is only true when "Other" is the filter value. That sheet would only display when "Other" is selected. I'm sure there are other approaches that would work too.
If you can post a packaged workbook (with dummy data if security is a concern), then I'm certain the ideas will flow from many here in the forums.