I did a terrible job of explaining the problem in my last post, so let me try again...
My manager wants to see sales vs. forecasts by day of week. We have sales data by country for each day. These all get lumped into "Domestic vs. International" and my boss is most concerned with comparing at this level, but if something is amiss, he'll want to drill down international by country.
The problem is we do our forecasts only at the domestic vs. international level. And when blending the data, every single country gets assigned the forecast that was intended for "international", which means that when aggregated, the sales make sense, but the forecasts are waaaaaay too high.
The packaged workbook should clarify the problem a little better.
Dan, this time around you explained your issue nicely, it make sense. Since you are not providing forecast data at the country level, how exactly would you want Tableau to calculate this? What would the forecast equation be? If you're not going to detail it by country in the db, then you'll need to tell Tableau how to do it using some sort of calculation.