I think there is only one heli operator in Whistler, I'm sure you can find them by calling Whistler's central reservations. A friend of mine did it last year and had a blast. The best part about (relative to others) it is that if the weather is not good, you can cancel at the last minute and ski the resort (they have an unusually lenient late cancellation policy). The other thing to make sure is that your entire group is of similar ability (speed), or some will be waiting and others will be struggling and feeling bad for holding everyone up.
...and Welcome to EpicSki!