Crystal Reports [CR X]delete a line as criteria

Message

   Hello all

I want delete a line if, for example, the delivery is already appeared in the document.

actualy :

Delivery 1234
    item aaa
        cost 1 : 10
        cost 2 : 15

Delivery 5678
    item bbb
        cost 1 : 10
        cost 2 : 15

Delivery 1234
    item ccc
    item ddd
        cost 1 : 8
        cost 2 : 12

Delivery 7777
    item eee
        cost 1 : 10
        cost 2 : 15

Delivery 8877
    item aaa
        cost 1 : 4
         cost 2 : 13

Delivery 1234
    item fff
    item ggg
        cost 1 : 8
        cost 2 : 12

I want to delete costs 1 and 2 of delivery 1234 when there is already the costs before :
the delivery 1234 apparead 3 times on my document

Delivery 1234
    item aaa
        cost 1 : 10
        cost 2 : 15

Delivery 5678
    item bbb
        cost 1 : 10
        cost 2 : 15

Delivery 1234
    item ccc
    item ddd

Delivery 7777
    item eee
        cost 1 : 10
        cost 2 : 15

Delivery 8877
    item aaa
        cost 1 : 4
         cost 2 : 13

Delivery 1234
    item fff
    item ggg

thanks for your help