I think I finally got it. I knew that I needed to get a mark, so the key was to use datasource 1 as my primary datasource and datasource 2 as my secondary datasource. Then I just created a calculation:
//Note: This is country for datasource 2, as you can see, my datasource 1 country field has a different name.
if ZN(count([Country])) = 0
"No Data Available for this country"