Towards the top right corner of the TWS Order Management Screen, you will see a "Trader Workstation/Ticker Lookup" search field.  Immediately to the left of this you will see a wrench shaped icon.  Click the icon.  From here, click on the Order Columns tab from the TWS Configuration window.  On the right side under Available Columns, click on Order Attributes to expand that selection and see all of your choices.  Click on OCA Group so that it is highlighted.  Then click on the Add button.  This will add OCA Group to the Shown Columns list.  Now click on the Apply button at the bottom of the window, and then the OK button.  The OCA Group column should now be on your TWS Order Management page.

Note: Because the OCA procedure is an automated process, there is no guarantee that requested cancellations and modifications will reach the specific exchange before an order has been executed.