Service Contract Conversion - Is there a way to prevent already billed lines on a contract from crea

We are converting service contracts and some of the contract lines have been partially billed in another system.  We are not bringing in any history for the lines already billed.  If we run Service Contracts Main Billing - it will create lines for AR for all the billing schedule that have already been billed.  Is there a way to prevent this or is there a workaround once the lines are in the AR interface.