Quote - Poser doesn't save multi-props as smart props, a bug since Poser4.
Poser only save as smart prop a single prop.
To make a multi-part prop smart prop you must do:
1- Select all the props and sve them in the prop library. It doesn't matter if the root prop has a parent or not, Poser always will save it as without parent.
2- Once saved, with a text editor find in the pp2 file the root prop and change the line
parent UNIVERSE  by smartparent your body part
ex: smartparent Head
    smartparent rRing2
In this way you can make every prop parented to a different body part, for example, loading a single armor prop you have each armor part parented to its respective body part

Stroke of genius, kawecki!! Thank you - that worked a treat.

My gemstone was already smartparent -ed to the setting, so I only had to do this:
replace
parent UNIVERSE
with
smartparent Head

I think the body part is case sensitive.

Thanks again: my partner and I were tearing out hair out! (not a good look in either Oz or Denmark... lol)

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks