OCO orders - close all orders in group

Can anyone help me please how can I write Stop loss order as OCO order? I don ´t know what I have to use as "MYGROUP" in this sintax.
I need cancel order used as stoploss when I close position.

ibc.PlaceOrder("MSFT", "BUY", 1000, "MKT", 27, 0, "GTC", False ); 
ibc.PlaceOrder("MSFT", "SELL", 1000, "STP", 28, 0, "GTC", True, 100, "", 0, "MYGROUP" ); 

Thanks Jan

"MGROUP" is an arbitrary name that you can choose yourself just like a variable name.

Just make sure you use a unique Group name for all orders related to a specific group.

It is the same as typing a group name in the order window textbox.

Thank you travick,
I suspected it would be something like that. Is exist something what what will by ganerate uniqe ID´s?