The feature is all good, but is there a way so that I could just add the major moons only? Like, I don't need all of the small asteroids that are orbiting Jupiter, it gets messy, and if you have a crappy computer, it can get really laggy. I really hope you're going to implement this in the next update, thanks
You can load the sim "Solar System Major Moons," then delete the asteroids by clicking Tools > More > Delete All Particles/Dust. There will be some lingering minor bodies, but it shouldn't be too hard to remove those.
Keep in mind that this many moons will still make for a very computationally expensive sim, as the accuracy needed to keep them in orbit is higher than, for example, keeping the planets around the sun. Still, removing the asteroids should help improve the performance a bit.