I need help - Outlook & Excel

Okay, here's the issue. I figured out how to break up a distribution list from Outlook (not Express) and transfer the information to Excel. Granted, I had to redo the box sizes and make more for first, last, middle names, etc. Now, I need to transfer it back into Outlook. The regular method refuses to work. Probably because I do not have the proper formula laid out. So, I transferred a simple contact to .pst and Excel and cut and pasted the former list to that Excel thinking well the newer one with the one contact should have the formula imbedded into it already. When I tried to transfer the list, again Outlook refused to accept. HELP!!