@thrice sorry to take so long answering but caught up in other things.
In principle this is possible. In this PG digits are parented to the first digit and the first digit parented to the box and the box parented to sphere Babylon.js Playground
Instead of using box and sphere multiple times in the SPS you could add individual pairs of meshes in the same way.
Of course whether this is a practical solution for your project depends on what you want to do with the meshes.
Good luck and I hope you find a workable solution.