1)
    reference   exchange_destionation
    1234          ""
    1235          ""
    1236          ""
    1237          ""

2) order_id_parent    exchange_destionation
   1234          XMAD
   1234          XPAR
   1236          XMAD
   1237          XPAR

3)
        reference   exchange_destionation
        1234          "XMAD" "XPAR"
        1235          ""
        1236          "XMAD"
        1237          "XPAR"

rs.ord$exchange_destination = rs.ord.hijas$exchange_destination[match(rs.ord$reference,rs.ord.hijas$order_id_parent)]

3)
        Reference   Exchange_Dest
        1234          "XMAD"
        1235          ""
        1236          "XMAD"
        1237          "XPAR"