Did that all the time and the most basic approach is still an option with the latest versions of FileMaker: Import Records.
You can use Import Records to move one or more records from one 5.5 file to another. If you isolate a record in a found set of just that record, Import Records performed from the other file, will import just that one record. If you want a script in File A to send the record to File B. Write the import records script in File B and use a script in File A to perform the script in that external file after isolating the desired record.
It worked -- thanks so much!