I’ll make some tests and write you back if I’ll succeed. In the meantime, there is also a thread that describes drawing a view-aligned texture on top of a Voronoi cell. View-aligned voronoi islands (for infinite forests, Eevee and Cycles)
You’ll have to replace the world up axis with z direction of your prop, and voronoi cell position with object position (Input - Object Info) and perhaps it’ll work even better