(Bullets Physics) How to avoid tunneling with compound shapes resembling rings?

Question

I've got some compound shapes built from four rectangular shapes resembling a squared frame, the idea is to use them as rough aproximations of rings

The rings are tossed around pegs, and several rings can be tossed simultaneously, tough ring collide with each other some times, they must not get stuck as chains

They get stuck due to tunneling, as is shown on the following images

Is there a way to avoid this "chaining" effect due to tunneling?

a) compound body, b) individual shapes, and c) top view

Answer 1

Why not simply just use a cylinder or box as your ring proxy? Do you really need things to be able to move through the center of the rings without collision?

A solid box volume should still roughly approximate your ring, but should be far easier to resolve tunneling issues for.