Creating PDF/A with linked attachments

Please help!

I have a word document where I have attached linked PDFs and they work perfectly fine when you click them open - in Word. When I create PDF/A (required from school) from the Word file, the links disappear. My understanding is that it is possible to create links to PDF afterwards, but the PDF/A form will not stay in the original format. And only the Adobe Pro version will be able to create these in edit mode - right?

In the linked instructions the advice isn't quite up to date, does anyone have some updated guide on how to add linked PDFs? And will they be visible to whomever the document (created from Word) is sent to?

One last question:

And will only other Adobe Pro programs be able to click on the links or will it work on all Adobe programs?