Adding form fields using anchors

Hello,

I was able to add form fields to a document using the REST Api v6. For the location of the form fields I have to specify the page, left, top, width and height value. This works fine so far so good. But furthermore I want to add a form field relatively to a specific word or tag working as anchor within the document, so my form field is automatically placed at this point, without defining a page. Is there already a way to do that or are there plans in future releases?

Thanks a lot.

Best regards

Christian