Although having multiple vendors for an item is a good idea, I am not sure we are going to be adding it to the program any time soon.
Please take a look at this forum post for more about this topic.
http://www.retailedge.com/phpBB/viewtop ... 767&p=2511
Maybe this will solve your problem as it has for others.
Hope this helps and let us know if you have any questions or need additional information to help you out.