Get sets of six unique combinations from an array given the range

I do have a problem, i have numbers from 1-49, now the question here is how do i get the maximum number of random sets of six from the given sample. like

int[] a1 = { 1, 2, 3 ,5,6,7 ... 49};

what i want is a six set combination like,

1,2,3,4,5,6
2,1,4,5,8,9
2,1,0,2,4,5

Until i get the maximum unique random values from the above