Multiple Wholesalers

I have an odd question and don't know if there is a Module for it or not. I have multiple wholesalers that I plan to upload their inventory to my site. Some of the wholesalers carry the same items but one may have a different item number.

Example

Company A has product XYZ listed as Model number XYZ

Company B Has product XYZ listed as Model number BXYZ

Basically I want to be able to upload both wholesalers but not have 2 of the same items listed with different model numbers. I want to be able able to "combine" both model numbers and have the quantity available added together. I hope this makes sense to some of you more experienced Zen Carters. If you need more details I can provide more details via PM etc. I greatly appreciate all the help on the forums.

Thanks
Mark