Puzzle family crisis solution

1) get the 2 fasters guys and cross the lake; 2) get the 1sec guy and get back; 3) choose the slowers guys and go; 3) 3sec guy returns; 4) 1sec and 6sec people go; 5) 1sec get back; 6) 1sec and 3sec guys go; PERFECT END (and there is 1 sec left... :D )