Double Sided Mail Merge 4x Postcards - Duplex merge data for postcards - Help

I am currently sending out post cards to hundreds of potential customers. I do all of the printing in house, and the optimal layout includes 4 post cards per page. These post cards are being printed in Microsoft Word 2007 and are populated from a giant excel (eventually a database) which mail merges the data into the final postcard file for printing. One side of the post card has the customers name and address. The other side of the postcard has the customers name and a specific price quote (This data is all in the excel file). The goal is to produce the postcards with printed addresses on one side, and their printed name on the BACK SIDE of that quadrant for the post card. Currently I can print 100 pages (400 cards) that have the parties names and addresses on the front side. When I try to either duplex or flip the cards over to print their name and specific price quote on the other side, the cards do not line up. For example, the front of the postcard will display the name and address and look like: ClientA ClientB ClientC ClientD But when you flip it over to print the name and price quote, they are out of order: ClientB ClientA ClientD ClientC This is a known issue and one solution that has been offered is to install an add in for Word 2007 located here: [login to view URL] This website is pretty good about explaining exactly what it is I'm trying to do. I can't seem to get this to work with my documents. Basically, I need some type of solution that will let me print four postcards per page, and have mail merged data print on both sides of the cards, in the proper spaces. I think the solution is going to require some type of script or macro that reorders the raw data in the excel file prior to completing the mail merge for the second page. I have attached three documents. 1) Sample excel file that has eight fields. This is where the name/price/address comes from and is the source for the mail merge. 2) Sample word file that is the front side of the postcard. 3) Sample word file that is the back side of the postcard. The ultimate goal is: Hitting print and having 100 pages print 400 postcards. Then I simply take the stack of 100 pages, flip them over, put them back in the printer, and print the other side which is now lined up. (I could also duplex this). Open to any and all ideas how I can make this happen.