Cube cart upgrade and mod

We need a new cubecart installing on a site and an upgrade of one on another site 3.0.10 to latest. Site A already has a cubecart installed, site B needs one installing. We need a modification to the backend of site A so site B's prices for items can be added in there. Site B will display the same products as site A just with the differnt pricing. If a price for a product for site B is not entered when adding a product on site A that product will not appear on site B. The payment and order management will be completely seperate on each site. Site A will have to update site b's product database automatically.