Is there a way to add assets directly to a Tax book?

We have some old FED books that have assets from a previous acquisition and they don't match the CORP book asset values.  The legacy FED book has these assets listed as groups so there is really no one-to-one relationship.  It appears the only way to get assets into the tax books is via Mass Copy (Initial or Periodic).  Is there any other way to get assets loaded directly into a tax book?