Mixing two displacements from two Daz shells in Blender
Okay, so here's what I have going on. I have created a G8M in Daz and imported into Blender via Diffeomorphic. The model has two shells: the "Authoritarian" for his man-bits, and Jepe's Body Hair Project. The issue I'm having is that both use Displacement nodes in their group output, but only the Body Hair's one is plugged in to the material output, as it's the last in line. Normally, without the Body Hair Shell, the Authoritarian plugs in. So I need to figure out what node to use in the Body Hair's group to combine both Displacement maps together. This is an issue because I've recently learned how to render using Cycles without my laptop burning my apartment down, so the Displacement impacts the result more than it does in Eevee. If I just have the Authoritarian displacment plugged in, the pubic area where the graft is looks washed-out. If I just use the Body Hair displacement, it also looks wrong (way more displaced) than the surrounding geometry.

Comments
I assume you're talking of diffeomorphic. Yes we adopted an approximation for material shells where only the top displacement is considered, now reported to Thomas to somewhat consider multiple displacements. Or you can use geonode shells instead, which will work fine with multiple displacements at the cost of duplicating the geometry, same as daz studio does.
global settings > shell method: geonode
https://bitbucket.org/Diffeomorphic/import_daz/issues/924/
update. This is fixed in the last commit, now multiple displacements are considered for material shells too, an approximation is used which may give slightly different results compared to daz studio. Or as noted above use the geonode shells for accurate results.
https://bitbucket.org/Diffeomorphic/import_daz/downloads/