Quote - Transparency on the undesired polygons is a non starter. One, it is slow to render.

But is the only solution that doesn't alter the geometry.
Altering the geometry in any except adding materials or groups will require redoing the setup and simulation (because you'd be starting with a new object).

Quote - It was brought up that moving the undesired polygons to a new group or actor or whatever would permit retention of the dynamics as well as setting visible to off on these polygons.

Visibility only applies to actors in a figure, or a whole prop (while a prop can have groups, for visibility purposes only the prop itself can be affected).