Sales order with reference to Contract and another sales order

Hi Gurus,

I would like your suggestions on one of the business requirement i have.

We are creating a new EDI interface with few of our customers to create sales orders. While creating sales orders, it should validate if there are any open contracts available and if yes, then the sales order should be created with reference to it. so far good but there are chances that sold to party on the contract could be different from sold to party on the EDI order sent by customer (customer can have more than one sold to party on their system). IDOC's are failing in this scenario and not able to create a sales order since sold to partys are not matching. I need your help.

Can we do some thing in customer master to handle this scenario?

or

Create a new sales doc type (YEDI or some thing) and create sales order from IDOC without reference to contract. Business will look into all YEDI order and create the actual sales order out of it but the challenge here is i cannot refer contract to the actual sales order or YEDI order.

Is it possible to create sales order with ref to a contract and another sales order?

Please help

Thanks

Venkat