Crosstable - make total of some rows (not all)

Adam11

<p>Hello,</p>
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<p>I have a crosstable like:</p>
<p>                 data1 data2 data3 ....</p>
<p>product1  1          3       5</p>
<p>product2   3         3       9</p>
<p>product3   2         2        2</p>
<p>product4   3        6         12</p>
<p>                </p>
<p> </p>
<p>It is possible to make a total  for instance: (row1+row3) instead of sum off all rows ?</p>
<p> </p>
<p>Regards,</p>
<p> </p>
<p>Adam</p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>

Adam11

<p>And one more info - I use Birt Version: 3.6.2</p>