I'm getting the concept now, some good ideas, I don't think we have anything of the sort in Canada. Innovative for a group with common interest to pursue it together for fun.
I think it very unlikely that you will find any organization who will (or is permitted to) do anything "aerobatic" with more than the pilot and one occupant. There are a couple of planes which are 4 seat aerobatic, but they are rare, expensive, and I believe can only have two seats occupied for aerobatic flight. So aerobatics, zero G, and dog fighting are not likely as a "team" activity, though participants could, one by one.
"Mile high" flights were flown in a Navajo at some point in the less mainstrean history of general aviation. I expect that such flights would proportionately very expensive, because even though you've take seats out to make space available, the operator of the plane will want a return for those seats anyway, so you're going to be spending $500+ per hour to send a Navajo up with three people aboard, as you still must have a seat for landing and takeoff for every occupant. For the same operating cost, you could get several more people up for a ride in it. Perhaps this would not be cost effective, but I leave that to the consumer to decide -
if you can find a source of that service. Some not yet seasoned aviators might prefer to enjoy the experience of being airborne, while airborne, instead of being totally distracted by a mate, which could be equally as easily be accomplished on the ground. Personal preference, I guess....
If you want to go for broke, have the group travel to Canada, and tour the eastern arctic:
Trek & expeditions » Rapid Lake
I did this trip in my amphibian last summer, and it was incredible. The operator does offer fly in for people who arrive to Montreal with no plane. Big cost though, you can just about pay for a PPL with the same sum!