Open Cart extension for multiple reseller access

I need to add the following feature to an existing Open Cart site. I have already obtained a copy of this extension so perhaps it can be customized. [login to view URL] One store which takes all the payments, but multiple resellers who will be responsible to ship depending on the buyers location. Basically there needs to be the following features: 1) User purchases goods we take the payment and they are shipped from us direct 2) User purchases goods we take the payment but goods are shipped from a reseller (reseller would have to have access to add shipping details and communicate with customer) Either 1 or 2 will be determined by the address the user enters on checkout. Attached is a detailed outline of all requirements.