Split matrix according to specified order of values
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sorry if this question's been asked before, but i cant seem to find an applicable answer!

i have a this sort of matrix:

    1  0.2   0.3    1  5
    1  0.25  0.36   1  6
    1  0.3   0.3   -1  5
    2  0.1   0.3    1  5
    2  0.3   0.3   -1  5
    2  0.6   0.4   -1  9 ......

the matrix is actually much longer and goes on to a value of 346 in the first column. How can I split the matrix up into smaller matrices according to a specific order of the values in the first column? For example, i need the matrix of all the values where the first column = 160, 130, 256, 2 in that order?

hope ive explained myself clear enough! thanks