How to call just once for multiple report....

Hi all,
I will have to make it possible for one administrator to see one hundred
user's report in just one time.
What I have done is that I just embedded the module which was passing the
parameter to sql reporting server in C# programming code by using looping
statement .
However,if it is the only way, consequently I will have to call sproc as
many as user's count. What it means the performance will be very poor.
I am really curious to hear that. Please could you give me any comment on it?Have another report, fetch for all users and group by user.