The filename is a private property of a file. Consequently, it is known only from inside the document corresponding to this file. As such, you can’t access the “slave” document name from the master.
However, the workaround is easy: in each slave document, add a new paragraph at head (or any convenient location, but head seems the best). This paragraph will contain Insert
>Field
>Other Fields
, Document
tab, type File name with the format you’d like.
I suggest also you give this paragraph a dedicated style, so that changing this style (in the master) to hidden will hide all the filename insertions at once for final production.
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