Calculating a value at a higher grain that responds to a lower grain filter

[tnwcloud]

Given a simple geographic hierarchy like Region>Country>Metro, I need to calculate a SUM at the Region grain that responds to a filter passed from a slicer at the Metro grain.

In a matrix I can create a measure [Regional Sales] = CALCULATE ( SUM ('BFT'[Sales],ALLEXCEPT('BFT','BFT'[Region])) and as long as Region is on the Rows before Metro it will display the total Region Sales for each Metro.

But what I want is a measure that will display the correct value for Region Sales if only Metro is on the matrix, or if the measure is put on a Card and a Metro is chosen in a slicer.

My real world case is more complex but if I can figure out this simple example I think I'll be ok. I guess you can't do attachments anymore so here's an image I hope clarifies what I'm looking for:

[wdx223_Daniel]

calculate([$ sales],allselected(BFT))