Printing a line after every subtotaling in ALV

REPORT  ztest_alv.

*---type pools
TYPE-POOLS: slis.

*---internal tables
DATA: BEGIN OF it_flight OCCURS 0,
      carrid  LIKE sflight-carrid,
      connid   LIKE sflight-connid,
      fldate   LIKE sflight-fldate,
      seatsmax LIKE sflight-seatsmax,
      seatsocc LIKE sflight-seatsocc,
     END OF it_flight,

*--internal tables for alv
     it_fieldcat TYPE  slis_t_fieldcat_alv,
     wa_fcat LIKE LINE OF it_fieldcat,
     layout TYPE  slis_layout_alv,
     it_sort type  slis_t_sortinfo_alv,
     wa_sort like line of it_sort.

*---start-of-selection .

START-OF-SELECTION.

CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
 EXPORTING
   i_program_name         = sy-repid
   i_internal_tabname     = 'IT_FLIGHT'
   i_inclname             = sy-repid
 CHANGING
   ct_fieldcat            = it_fieldcat
 EXCEPTIONS
   inconsistent_interface = 1
   program_error          = 2.

*----get data
 SELECT carrid
        connid
        fldate
        seatsmax
        seatsocc
  FROM sflight
  INTO CORRESPONDING FIELDS OF TABLE it_flight
  UP TO 20 ROWS.
 .
 wa_fcat-do_sum = 'X'.
 MODIFY it_fieldcat FROM wa_fcat TRANSPORTING do_sum
  WHERE fieldname = 'SEATSOCC' .

  wa_sort-fieldname = 'CARRID'.
 wa_sort-group = 'UL'.
 wa_sort-up = 'X'.
 APPEND wa_sort TO it_sort.

  wa_sort-fieldname = 'CONNID'.
 wa_sort-subtot = 'X'.
 wa_sort-up = 'X'.
 APPEND wa_sort TO it_sort.

  CALL FUNCTION 'REUSE_ALV_LIST_DISPLAY'
   EXPORTING
     i_callback_program = sy-repid
     is_layout          = layout
     it_fieldcat        = it_fieldcat
     it_sort            = it_sort
   TABLES
     t_outtab           = it_flight
   EXCEPTIONS
     program_error      = 1.

The output would be similar to this: