Calculate a virtual char comparing aggregate data (totals) of a query

Hi all,

i need to calculate a characteristic using a BadI in BW and the logic is quite simple: i need to compare the value of two calculated KPIs in BEX so if KPI_1 > KPI_2 then CHAR = 'OK' else 'KO'.

The problem is that i need to do this comparison on the aggregated data i have in the query but using the badi i can only compare the values on the single record.

Also another problem is that one of this KPIs is calculated in BEX and it's not in the infocube (i'm using a formula variable to pull master data attributes)

How can I create such characteristic?

Thanks

Stefano