exclude selections apart from 1 field

[#1]

Hi,

can anyone tell me how to exclude current selections apart from 1 field.

I have the following expression..

=max({1}[EventDate])

That excludes all current selections, but how do i tell it to allow selections made on the EmpID field?

Thanks

[vivientexier]

Sum({< EventDate_num={">=$(=Min(EventDate_num)) <=$(=Max(EventDate_num))"}, EventDate_num= >} KPI)