The game is simple. With a couple Genjis seperated by a “net” made of two Mercys healing and/or buffing each other you just have to get one Junkrat to stand above and fire off, well, shuttlecocks in the form of his grenades. 

If the Genjis can time everything right they can keep deflecting the grenade back and forth until someone drops it and goes boom. 

Sadly, there can’t but a full destruction means for this little meta game since the Junkrat HAS to be on the same team as some of the Genjis.