I played this situation yesterday (on PC)
Enemy team had 5 Torbjörn and 1 Symmetra. I told my teammate to take full snipers. I personally prefer widow but it should works with Hanzo as well. Take widowmaker, only focus for the turret. If one Torbjörn is coming to you, try to kill him but when you have enough time to: Scope, 100%, shoot turret, hide, do it 3 time and even if he repair the turret, it will get destroyed. Always go for the most on side turret. Once you cleared the first, go for the second. If you see a Torbjörn creating a turret, destroy it immediately, in one shot it should be destroyed while in construction. Don't even bother killing the Torbjörn in that case -> no turret for 10 sec is enough to destroy more. If he recreate again, do the same thing, if you are 2 or 3 snipers, they shouldn't be able to construct more turrets. If they want to construct one they'll have to do it a bit more far. So you can move your payload for some meters, then do the same things over and over, win 10 meter by 10 meter, they HAVE TO go back to make more turrets, so it's good for you since the only thing that count is to get the payload at destination.
More of that, I played on Hanamura versus 2 Torbjörn with a widowmaker yesterday, was in attack on site B. Torbjörn can really be useless if you have a widowmaker, once you destroyed his first turret lvl 2, he'll never have time to put one more turret since you one shot it. Please if you see a Torbjörn and you are your team sniper, just focus for the turret! it take one shot to destroy them once you destroyed the first and the Torbjörn will be useless during the whole game. You have like 10-11 second before the next turret so you still can make kill then, but at first you really need to focus for the turret since really few heroes can do something against it.
About Reinhardt, it's great when their is one turret (and even their, if other enemy's heroes have mobility, you have to face the turret, and if they come behind, either you let them kill you, either you turn and the turret kill you really fast, so it's not a "long-term" option, it's in purpose to destroy the turret), but if they are multiple, Reinhardt can't do anything about it. I really think that if you have 4 or 5 Torbjörn against you, you should have 2 or 3 snipers, all the Torbjörn will be useless if you focus for turrets, one widowmaker can handle two Torbjörn, so if they have 4 Torbjörn, you take two widowmaker, only focus for turret you'll be 2 widowmaker unable to do anything else, but 4 Torbjörn will be useless too and your team is now 4 versus 2.