Need help transposing Rows into 3 equal columns

Hello everyone. I am new to this site and I have been reviewing some great post from the members and admins here. I hope you're able to help me with my problem.

I have created a batch file that automatically creates a directory listing of any folder that I choose. I have made it so that it saves the listing as a csv and opens the file in excel.

I am getting stuck because I need to be able to break that list down into 3 equal columns.

Ex:

a
b
c
d
e
f

into: a b c
d e f

I have tried to transpose but it spreads the list completely over the total amount of columns. Is there anyway to limit the range to 3 columns?

Thank you again for your help!