Import Blanket Purchase Orders without Ship and Line Info when implementing Oracle

Our company uses Blanket Purchase orders in a Legacy system which creates unique release numbers for individual transactional requirements from our suppliers.  Each of our purchase items are set up one-to-one with these Blanket Purchase orders so a request for a certain quantity to be delivered on a certain date for a specific item would have the unique release assigned to it.  We would like to import these Blanket Purchase orders as Local BPAs during our Oracle implementation and maintain the previously created unique release numbers as the release numbers in Oracle.  This would keep our Supply Chain communications consistent