Frank Smith wrote:

Try using regular expressions to split your subdirectories.
Many people on this list wildcard the end of the name, such
as /data/1*, but for your application I would suggest wildcarding
the first digits instead of the last instead, such as /data/*1,
since the first digit(s) of your customer numbers are probably
less evenly distributed than the last. If splitting it into
10 chunks isn't enough, you could try something like /data/*1[0-4]
and /data/*1[5-9] etc.  and split it into 20 DLEs.

Thanks everyone!
Cameron Matheson