I have a FilemakerPro database with many records that I need to send as an XML file to the EPA. I can export as an .xml but I need to add headings and structure the file in a nested format. Is it possible to create this type of file with filemaker? If so, any tips on getting started?

Yes. If you use an XSL stylesheet (which you really must), you can arrange it how you want, and add what you want. You really need to export the xml from FileMaker without a stylesheet first, and see what you got. In particular pay attention to the result of exporting related fields, such as those in a portal. It is in a different, though logical order.

Then you need to look at what the resulting xml should look like. Hopefully you have an example of that. Then it's just a matter of creating an xsl that transform FileMaker's xml to the desired xml. Not so simple, but doable.

The "headings", if they're just fixed text, can just be added in a element. If you require data from FileMaker fields in the heading, you'd use the [1] specifier to only get data from the first record .

There's likely examples here in the xml forum that would be similar to what you need, but not exactly the same. The "X" in XML is for "extensible".