If I understand correctly:
01 TEN-DIGIT-NUMBER.
05 TDN-FIRST-TWO PIC XX.
05 TDN-LAST-EIGHT PIC X(8).
Study the manuals about how to define data, REDEFINES can also be very useful for this sort of task (and could be used for your requirement).
01 TEN-DIGIT-NUMBER PIC X(10).
01 FILLER REDEFINES TEN-DIGIT-NUMBER.
05 FIRST-TWO-OF-TEN-DIGIT-NUMBER PIC XX.
05 FILLER PIC X(8).