Service order quotation

Hi All,

While creating the service order quotation..in the line items I have to populate the higher level line item by default or automatically..Please see the attachment for more details..

If suppose if I have 3 line items 10 ,20,30 I have to populate higher level line item for 20 and 30 as 10...we have to exclude the line item 10.

I need some ideas how to handle this scenario..like which is the best way to achieve this..

I appreciate your help on this..

Thanks,

Susan..