Dynamic hierarchy Visual Level selection by slicer selections

I have a scenario of three level hierarchy location (Region->Districts->Blocks).I want to see location wise values in the donut chart.But the requirement is when I select region ,donut is showing the value for complete region instead it should show values for all the districts in that particular region.

Like wise if a particular district is selected it should show all the values of block in that District.

And by default View it should reflect all the values of regions

Dax Measure:

sales_by-Level = If(Isfiltered(country[Region]),Calculate([Inqty_sum],'Level'[custom]="L1"),

                  If(ISFILTERED(country[District]),Calculate([Inqty_sum],'Level'[custom]="L0"),

Calculate([Inqty_sum],'Level'[custom]="L2")

))

By using the above Dax measure Now if I select Region in slicer its showing District values.

And If I select District its showing block values.But When I select Both (Region& District) its uanble to show the block values.

I Have attached the screenshots for better understanding in the link.

Please correct me.

Thanks