Once in a blue moon, I want to work with a spot cross-reference … I run into the same question every time, and promptly forget the answer. The illustration in my battered copy of the FM 7.0 User Guide seems to show exactly what I want to achieve, a single word defined as a marker and then showing up elsewhere as a hyperlink. My problem is, I can't work out the building block to use in the cross-reference format: I was expecting something like <$markertext>, but don't see it. I tried <$paratext>, but that was a bit too generous :-}
That specific request, a generic <$markertext> building block, has been on the wishlists for a very long time...
The possible workarounds are listed in the thread that Error points to.
> I tried <$paratext>, but that was a bit too generous :-}
... only for excessive values of paragraph.
By using run-ins, a paragraph could be a single letter if necessary.
If I had but a small number of such spotrefs to do, I'd use dedicated Xref formats (where the format def is just the desired string). This is described in the referenced thread.
I use spot xrefs extensively. Although you can easily generate a reference to the location (as in "See the screen capture on page <$pagenum>) there seems to be no way to leverage the markertext content itself.
I agree with Arnis that this is a long-standing need, and one that should be considered by Adobe for development.
A side-note: Conversion of Fm to Rh may require mapping these xrefs to a text string instead of [Source] or various building blocks.