Before You had to click and drag over hundreds of contact(s) info in Microsoft Excel, however now You Can use this Simple tool.
It basically takes Your large email list(s), and breaks it down in to smaller more manageable sizes.
120,000 contacts in csv format Can Be broken down in to 6-20,000 or 2-60,000, etc… What ever cluster sizes You want, this software does it in a few Simple steps.
Mailing List Manager tool:
Here are the Instructions on how to use the software: