That feature is good for combining multiple reservations into one group. It does not change the reservations at all. So for example, I am flying to HKG next week and have 4 seperate reservations booked for the travelers in my group. I was able to "combine" them into one group that I named "Hong Kong". If you book a car and a hotel through co.com, you can also add those reservations to you group or trip to manage them easier. All in all, I really like the feature. ^