Can you supply a packaged workbook?
Or at least hack up an equivalent sheet in Superstore and upload that? Some of this will depend on what your sheet looks like.
You can create a calculated field called sort value that keys off of your parameter - something like this:
when "Supplier" then [Supplier]
when "Country" then [Country]
Then, for the dimension that you want sorted, go into the sort menu and sort it by this calculated field. When you change the parameter, the sort will also update.
Thanks for your time , awesome