Apply Break based on the Dimension Group

Hi Friends,

     I got a requirement in one of the webi report as shown below, where the record below has two lines on the 'shipment' but this corresponds to one 'Delivery Document'; since Delivery Document Item is 2 (10 and 20).  The freight cost should be calculated based on the total weight of the shipment  of 18632.16 kg.  The 'freight cost per LB' for this shipment should be $1,613.70 / 18632.16 LB =  $.0866 per kg.

Can you help me how to acheive this in all my breaks results?

Thanks

Santhosh Kumar N