ConfiForms: Can I reference a child-page, is the parent page is chosen in "page"-field?

[Christine B]

My form is constructed, so that by "Page/Blogpost" a page is chosen and a File/Attachment is uploaded.
This page has child-pages, and one of them is called something like "Documents - 20.10.2025". I want it to move the attachment to that child-page.

So my pages are structured like this:

Page A

--- Documents - 20.10.2025

--- Other Page 1

--- Another Page 2

Page B

--- Page 3

--- Another Page 4

--- Documents - 21.01.2026

...

So each parent page has several child-pages and one of them is always called "Documents -*", which is the page i always want it to move the attachments to. So Page A or Page B would in this case be the ones chosen in the Page/Blogpost field.

Is there an automated way to do this? I tried working with calculated fields or using something like "[entry.Zuordnung.asPage.children.get(0).id]", but with that, the child pages would always need to be in the same order, which they are not.

Thanks in advance for any solutions!