When a Cash Type client specify a sell order to offset a buy order
and demand a cheque for the particular transaction, it will be helpful to use
this function. User of this function can mark numbers of transactions to be summarized
with a single cheque.
當客戶要求將指定之買賣單合併計算, 並將所得餘額以同一支票印出, 就要用到這功能.選擇合併要在輸入交易單前預先知道,
才可以在輸入時將有關之買單及賣單交易標記為比兌及出在同一支票