List Splitting

[Steven]

Hello everyone,

I'm trying to work through a bit of a logic issue I'm having with a
script I'm writing. Essentially, I have a list that's returned to
me from another command that I need to regroup based on some aribitrary
length.

For the purposes of this question, the list will be:

t = [ "a", "b", "c", "n", "a", "a", "t", "t", "t" ]

Now, I know that every 3rd element of the list belongs together:

Group 1 = 0, 3, 6
Group 2 = 1, 4, 7
Group 3 = 2, 5, 8

I'm trying to sort this list out so that I get a list of lists that
contain the correct elements:

Goal = [ [ "a", "n", "t"], [ "b", "a", "t"],
["c", "a", "t" ] ]

The actual data isn't as simple as this, but if I can get the logic
sorted out, I can handle the other part.

Anyone have any good ideas on how to do this?