reymundo,
in the previous system that i developed, there where 26,000 doctors and the med reps have an accumulated 600,000 record calls (annual). it may have some waiting time, nonetheless, it still worked. you won't be using all that data at the same time, would you? break it down.

you could also use a cursor to store the results of an aggregate function (i.e. sum, count, max, average) in an sql query while in a looping statement.

ex:
use {table/s}
index on group
get groups
create cursor
loop for each group
thisgroup = whatgroup
do while {thisgroup}
SQL Query for this group
Save Results into cursor
enddo
endloop