The Destination store should be able to override the billing details entirely with their store info on order push to Source store, so the Source store can mass bill the Destination store on their own basis depending on contracts.

I would assume there are a lot of companies that prefer to bill their destination store on a per month basis instead of sending the funds straight to the client, right now I've been told the workaround for this is to use the orders module so you can push the destination stores email through and filter the orders like that, so this request is essentially an extension of that.