Pick a strong but incredibly safe (RUNS AWAY GOOD) top laner and split push all game (garen/singed/udyr, tryn prolly works). If the other team doesn't stop you with good ganks (ganking garen or singed is impossible) then you just removed their top laner from the game while he pointlessly tries to hold you off and you take turrets. If you're getting ganked, you should easily live and your team is free to fight 4v3/2/1 or push a turret or take dragon.
If you don't crush your lane though then just group, no point in split pushing if you can't 1v1 everyone on the other team.
That's what I did every single top lane game I played, and a lot of my jungle games too when it gets to that point.
If you think anyone below diamond can deal with split pushing consistently, you're wrong.