Shipping Calculations with Multi Dimension and Multi Vendors

Looking for app advice that do both shipping and fulfillment.

Here’s our problem: We have a store that uses dropshiping with multiple vendors and thousands of products. Currently I’ve created different shipping profiles (some for different vendors and some that are general) because due to shopify’s single dimension package we are only able to set flat rate shipping based on averages. We are also using Order Fulfillment Guru as our fulfillment app to send orders to vendors. Vendors are using their own shipping methods but we’d like to be able to charge the customer more accurately.

Is there an app the will work well with Order Fulfillment Guru that could help us calculate shipping better? We have used ShipStation but don’t want to have something our vendors have to log into.

Check out Cloud9express.com