Show Only a Subset of the Legend Items in the Legend Card

Unable to show only some of the legend items in a visualization

User-added image

Build a full data worksheet and a filtered data worksheet and then combine them in a dashboard.

Build a normal pie chart in a worksheet and name the sheet Full Pie.
Create a calculated field Total income: TOTAL(SUM([Income]))
Create a calculated field test: SUM({ FIXED [Region]:SUM([Income])}) / [Total income]
Duplicate the worksheet Full Pie as Custom Pie.
Drag test to the filter. Set whatever range desired.
Create a dashboard Combined Chart.
Drag Full Pie and Custom Pie to the dashboard.
Remove the legend from Full Pie and keep the legend from Custom Pie.
Float Custom Pie and minimize it somewhere in the dashboard.