Xlsform - use XPath in label

I know that with xlsform I can reference the value of a question/calculation from the label of a different question by just including the variable reference in the label text:

type name label default
string world WORLD
note hello_world HELLO ${world}

However, I am wondering if the same is possible when I want to use an XPath instead of the variable:

type name label default
string world WORLD
note hello_world HELLO ../world

This does not seem to work for me, but I am not sure if maybe I am missing some syntax.

I found this thread which seems related and makes me think:

this is not exposed in XLSForm

But I wanted to see if perhaps I misunderstood what was being discussed in that thread or maybe something has changed in the intervening years.... Thanks!