You can script the export records process. That will allow you te export the records in exactly the same fashion each time. You could, for example, find your records that you want to export, then click a button to export the data consistently. You may even be able to include finding records as part of your script--but that depends on details you know and I don't.
Thanks for your input. I did find the solution: I export all the fields in my FileMaker database to Numbers.
Since I have created templates for my invoices, scheduling notices, initial letters, etc. in Pages, when I save the exported fields in Numbers that is the source for Pages, only the fields in each individual document are merged.