Help with calculated listbox

[michael_maeuser]

Hi, I have a listbox with this formula:

aggr(
if(
RangeSum(Above(
sum(if(Date=Today(), Lagerwert))/
sum(total if(Date=Today(), Lagerwert)),0,500))
<=$(ABC A),'A',
if(
RangeSum(Above(
sum(if(Date=Today(), Lagerwert))/
sum(total if(Date=Today(), Lagerwert)),0,500))
<=$(ABC B),'B',
if(
RangeSum(Above(
sum(if(Date=Today(), Lagerwert))/
sum(total if(Date=Today(), Lagerwert)),0,500))
>$(ABC B)
,'C')))
,Product)

So in the listbox appears A, B, C. Now I need to tell QV, that it starts cumulating (rangesum) with the product having the highest value out of sum(Lagerwert). It´s a ABC-Analysis and this is the way the table chart is and must be sorted. I hope this is makeable. Thanks in advance! Michael