Get a total on rows that are filtered using the Group Filter in a Table

Is it possible to get a sub total for a Top N filter?
I've got a group that contains that contains a top N filter.
This filters properly for example, I see only 3 rows per group.
However, I cannot get a sub total for only those 3 rows. It calculates
all
of the rows with the main group.
How would I get the sum for only those 3 rows that are being displayed
on
the report.hi,
keep a visibility condition for other subtotals. i mean to say to
select each three records you would have taken mod ,right? take
absolute value now for not showing other totals
some thing like this
Rownumber(Isnothing)\3<2 such that it will be invisible for that row
Thank you
Raj Deep.A