That can be done now, with areas like a brow overlay or lashes, but it does require a comparison to a source object. Basically, the overlay areas are set up to receive the same deltas as the underlying faceskin material. I've been doing this since P8 days, with Antonia. Because of how TDMT was designed -- the limited scope of the project -- there is no setup to allow one material to receive deltas from another material on the same object. A workaround, however, would be to use two instances of the same object to achieve that same goal. The source object should have the faceskin equivalent deltas and the second object's overlying brow/lashes/whatever materials should be correlated to the faceskin. I've used that trick a few times while refining face morphs.

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Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.