Messaging Interface

Hi.
I am looking for messaging interface solution that will allow a customer and a dealer to communicate through my website but without being able to commicate directly with each other outside the website. My business model is similar to ebay in that customers sometimes feel it necessary to go outside the site and avoid commission. I want to be able to see what what is being said between both parties. I guess what I'm looking for is a system where the business is the messenger.
Thanks,
Jonathan
 
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