Calendar - How can I expand the recurrences of a recurring item in ItemAdding event receiver?

When a user add a new recurrence event to a calendar I want to check if any of the recurrences overlap with events already in the calendar. I saw the property Recurrences Data and its XML but I didn't find a way to translate that value to dates I can test against the events dates on the calendar. So, is there a way to expand the recurrences of an event in the ItemAdding event receiver of a calendar?