There's a comparison to what I'm talking about on a larger scale: Jupiter's got its Trojans and Greeks, and Earth does have them too. Those are more or less loose and sparse groups of asteroids that stick on their parent object's L4 and L5 points. There's no comparison (as far as I'm aware, though I may be uninformed) to it on a smaller, planetary scale. Jupiter's rings are too sparse for it to be noticeable, Saturn's only significant moon, Titan, is far away from the rings. That got me wondering, how would a system like that look. A system without just and only regular, circular rings, but also with a major moon, would add the complexity and uniqueness of the system by transforming some of those rings into its trojans.
If there were a major moon inside, or on the outer layers, of a planetary ring system, would the ring's particles, which would accumulate at the moon's L4 and L5 points, be there for an extended period (talking about hundreds of millions of years) or would they be too unstable and would start accumulating or colliding with the planet or the moon? Or maybe they won't be able to establish themselves there in the first place at all?