Render Multiple Particle Systems Separately?

I have a landscape scene where the terrain has multiple particle systems, two types of grass, two types of trees. It is too much for my computer to handle. So I was wondering if it was possible to render each particle system separately? The problem is that the trees and grass need to cast shadows on each other and mask each other out. Is there a way to pull this off?
Thanks!

Compositing is good for combining background & foreground renders, but your problem sounds more complex.

I’d recommend setting the viewport particle count lower than the render count. Then you can navigate smoothly and the render should still work.

Another thing is alpha texture grass is slower than actual geometry with a simple shader for some reason.