add extra fields which are for selection like below
Sum({<Shop= {'Pomax Store Wijnegem'}, Year = {$(= Max(Year))}, Date = {">=$(=Date(Max(Date)-90)<=(=Date(Max(Date))))"},Date=,Year=,Shop=.... >} LineSalesAmount)
you can add like above Date=,Year=,Shop=, and whatever field you dont want to affect this sum