Launch options/switches for Opera browser

Is there a way to alter the launch options from the PortableApps launch platform to add a switch at the end of the shortcut path? I need to be able to launch the browser in private mode every time. That requires the " --switch" at the end of the launch path in the shortcut. I need something like this:

"\PortableApps\OperaPortable\OperaPortable.exe" --private

Can it be done? Launching in private mode is not an option in the software's settings. Its getting very tedious having to manually make this setting every time I launch Opera browser. Furthermore, the ability to add switches is also useful for other portable apps besides just Opera.

Thanks