EBS GL Mass Maintenance for range of Periods

My client is having a tidy up of their Chart of Accounts, mid year. We've looked into using Mass Maintenenace, however even if the new GL codes are only open from the beginning of the current year all the periods all the way back to when we implemented R12 are Moved and Merged. We just want to move for current year, we do not want to move prior years as we need to be able to report on the old codes for these years. If we just journal the current year balances we lose the drill down capability to originating