There's more than one way to "combine" arrays.
Look at the BUILD ARRAY function.
If you wire three arrays to three inputs, you have a choice of outputs:
You can CONCATENATE the inputs, in which case the output is a longer 1-D array.
If you DON'T concatenate them, the output is a 2-D array, which sounds like what you want.
You will probably want to TRANSPOSE the 2-D ARRAY, as this will give you three columns of N rows. Without transposing, you get three rows of N columns.
If the original arrays are not equal length, they will be padded with zeroes.