Dax help for measure on stacked column chart that's filtered

[mistericulus]

Hi PBI RS Army,

I am seeking guidance on something that seems like it should be simple but is proving to be challenging:

I have a stacked column chart showing sales of various items of winter apparel by region (N, S, E, W)

Some items (like gloves) are sold in all regions (this is completely fabricated sample data).

I have two slicers: 

1. Category = gloves

2. Region = only East and North (excluding West)

I also have a tooltip tab that pops up when hovering over any of the elements of the stacked column chart as shown:

The challenge I'm having is getting the measure (sum of sales measure) to reveal the sum of east region + north region (only) on the tooltip which is shown when hovering over either of the East or North region segments of any of the years.  My formula for that measure is:

sum of sales measure = CALCULATE(SUM(DATA[SALES]), REMOVEFILTERS(DATA[REGION]))

Because I have the removefilters(data[region]) in the filters portion of the dax, it includes all three regions (including West).  But of course if I remove that removefilters(data[region]) portion from the measure, it'll only show the sum of sales for the region over which I'm hovering.

Any guidance appreciated.