Logistics expenses should not be copied to while Creating Debit/Credit memos w.r.t customer invoice

Hi

First of all thanks for your efforts please.

My requirement is.as below.

1) while creating the Credit/Debit memos directly from customer invoice (F2) documents, logistic cost conditions ( around 10 conditions) from F2 invoice should not be copied into credit/debit invoices.

( crating  wrt invoice F2 to invoice L2/G2)

Please let me how to achieve this very urgent .

Thanks all.