Message Aggregation scenario

Here is my problem..

I have an inbound message which is generated from a flat file . This message actually a set of identical sub message in a envelope. I am passing this message to the orchestration.  From the orchestration I need to pass this message to Business Rules engin to modify some of the fields basedon the business rule policy. I have a web service which inserts these individual messagesto Database.

My Web Service has the capability to process Insert request in Batch.  But My problem is that, for doing the business rules processing, i need to send single message, because the processing will be different based on the input values in each message.  I split the main message using a looping construct and Xpath, and send to rules engine. Now I want to combine these messages as a single one before mapping to my WSDL schema.  Any Idea how can I do it within the orchestration..?