How to use BOL Core instance in 2 sessions in Parallel processing

Hi

We have developed a BOL program which uploads repair order flat files from non-SAP system to SAP CRM system. The Data to upload is huge that we are facing performance issue in QA environment currently. It was identified to apply parallel processing in the program so that it may overcome from the performance issue.

Now the challenge is How to use BOL core instance in 2 different sessions, since parallel processing will open in different sessions and Asynchronous RFC doesn't accept Reference variable as import parameters.

Anyone worked in parallel processing sharing BOL Core instance. please let us..

Thanks in Advance.