The hammond theory starts with piledrive. So first squishy shouldnt be used on defence. Good thing Mercy has enough mobility to run at best timing.
Now the tanks should also do something I guess. Dva is the best option first, she can shred winston midair unless enemy dva guards him. That will keep dva busy and winston himself doesnt have big damage so another tank like hog or reaper brigitte maybe can stall him.
Another support? Hard to say, Zen is too risky but his orb does help against tanks so he would stay behind I think.
Will this work? Maybe maybe not