Just having a play around with sps, wanted to see if I could come up with a simple collision system from scratch. Only designed to work with spheres.
http://www.babylonjs-playground.com/#1C2HFL
http://www.babylonjs-playground.com/#1C2HFL#1
less segments http://www.babylonjs-playground.com/#1C2HFL#2
Have a play around with number of particles, size of particles and max speed. Max speed should be less than radius, too big and the particles escape.