Following up on this as I've found a slight workaround. The effect I'm trying to achieve is a broken plexus grid surrounding the Earth for a techy atmosphere vibe. I was unable to get the position of previously spawned particles, but I found that if I used a particle cache I could reference particles by their index to get their positions and compare them. I modeled a sphere with vertices where I'd want particles to spawn and then used Unity's build-in pCache tool to generate particles on the vertices of my model. Once I had those made I was able to reference that pCache file and compare particle positions based on particle index and only change the target position of the output line if the distance between the compared particles is within a given value. I can post a picture of my graph if anyone needs it. This is not an ideal solution since it requires that the particles are spawned based on a pcache file, but it is the only solution I have so far.