title: Is it possible to create a custom equation in the group summary in COGNOS version 11
body: <p>I’ve created a report in COGNOS which groups all duplicate orders together which works well.</p>
  <p>I’m trying to work out if there is a way to do a custom equation within the group summary to total the value for all entries within the group but then minus the first line within the group for a total.</p>
  <p>The first entry within the group is the received order all others are extra orders received but are human errors. My hope is to have my report show a value for all the group total and then the group total minus the first value.</p>
  <p>The total summary at the end of the report should then give me our final figures.</p>
  <p>This way I can work out what we have paid for original orders and then when we have paid for extra unwanted orders. I’m hoping this makes sense.</p>