Welcome to the forum, and sorry to hear about your poor Jazz.
It's obviously possible, but difficult to say if there will be any damage to the gearbox. If I had to give an opinion, I would say probably not, but it certainly won't have done it any good.
I'm guessing this will be an insurance claim? To be honest, if it's been rear ended hard enough to push it that far, I would think it would be a candidate for a write off, especially if they suspect there is any possibility of drivetrain damage. It doesn't take a lot to write a car off these days, unless it's a very high value vehicle.