You want to buy some tech stock at the best possible price, but you only want 100 shares. You could buy 100 shares of YXX at 25.00/share, XYZ at 19.50/share, or YZZ at 21.40, but you don’t want more than 100 shares total. On the Page menu you select Layout, and in the Columns – Order Row section you check the OCA Group box. On the trading screen you click the Ask price and create a buy limit order for YXX at 25.00, and in the OCA Group field you type in “Tech.” You then create two more limit orders, one for XYZ and one for YZZ at the above stated limit prices, and in the OCA Group box you enter the same name, “Tech,” for each of these orders. You have created a one-cancels-all (OCA) group. If one of the orders executes, the other two orders are automatically cancelled. If one of the orders partially executes, the quantity of each of the other orders is reduced proportionately. If an order in the group is cancelled, the remaining orders are also canceled.