You can export certain types of transaction from one file to another without using a third party application.
To do this you must meet the following criteria:
Step 1: Set preferences appropriately to allow the export.
Step 2: Create a Custom Transaction Detail report for each type of transaction you want to copy to the new company file.
Step 3: Export the report to Excel.
Step 4: Enter transactions into new company file using the Batch Enter Transactions screen.
NOTE: This process will work in an Accountant's Copy as long as the transactions dates are PRIOR to the dividing date.