Case 1: A batsman can be given out

1st batsman hits a six....gets caught on d nxt ball...crease
is changed....next batsman hits a six again...

Case 2: No batsman is out

1st batsman hits d ball n hits d keeper'ds helmet kept
behind...he also takes a single...6 runs are added to his
total making it 100...on d next ball ,2nd batsman hits a
six,making his score 100....as simpl as dat....

first batsman hits a six in first ball among three balls
second batsman hits another six in next ball

Lets make it interesting! Sachin and sehwag 94* each with 3 balls to go in the final over of the match, requiring 7 runs to win (and sehwag cursing his luck to be at the bowlers end). Sachin hits a six and completes his century (scores are tied) but develops cramps and is forced to retire hurt (couldn't hit the winning run,poor chap.) New batsman Ganguly attempts a run off the next ball which luckily is a dead ball but he doesn't get that lucky and gets run out at the bowlers end, lucky sehwag hits a six and completes his century!
N.b- feat can be achieved in just two balls.!!

first ball is 4 by first batsman,
second ball , its goes for 3 but because of not touching 
the screeze it is added only two for first batsman, so he 
completed 100 and also strike goes for second batsman;
last ball second batsman will have one six;