How can I create a column vector by taking only the maximum values from each three values of another column matrix?

Hello This is only an example, say that I have a column vector of 99 rows contains number 1 to 99 such as c=[1:99]'. Now I need to deduce another column vector d from c where I will have the highest value from each of three values of C. So the first row of d will be 3 which is the highest value of first three rows of c, the second value of d will be 6 which will be the highest value of the second three rows c and so on. Values of consecutive rows are not arranged in any particular order. Can anyone help please? In this example d will come out as: d=(3:3:99)'.