Min date slicer value ignoring visual row dates

Hi,

i have a report with a date slicer ( hierarchy list ) and a matrix with dates on columns and measures on rows. I want to show min selected date of slicer on each visual row ignoring dates on columns so that i can use it in another measure on visual. 

I have tried ALLSELECTED() function but works only when i drill down to date values. 

expected results : 

selected dates : 1/1/2020 - 31/1/2021

current results : 

selected dates : 1/1/2020 - 31/1/2021

Is there a way to ignore dates on  visual and use only selected date (min) from slicer?

thanks,

Maria