How to sumarize only certain records in a Crystal Report

Hi,

Can anybody help me how to sumarize only those records which field by which they are grouped has certain value i.e. ex. for group 1 where id<=10 total ... and group2 id>10 total=....

ex.
Group1

 id  sum
 03  112
 total  112

 06  55
 06  15
  total  70

total for the Group1 182

Group 2
 id  sum
 22  142
  total  142

total for the Group2 142

I  tried to insert formula field:
If({DataTable1.idpod}<="10")then Sum({DataTable1.Iznos})-If({DataTable1.idpod}>"10")then Sum({DataTable1.Iznos})

but it summarises all the records regardless the value of id.


  Thanks