Hi
As far as I know only meetings in the normal calendar will be fully functional.
You could get creative with a macro. For example if an entry enters the personal calendar and has a certain keyword or category as a property the macro kicks in and copies the meeting to the sub folder. All responses (accept / decline) should still be done from the original item. Using some imagination you could think of a macro that monitors the interaction with the copied meeting in the subfolder and instead uses the original item to communicate with the organiser.

regards,
John