how do i make particles travel to a set of coordinates?

I'm trying to make a block that can be linked to another of the same block, and I'd like for there to be a trail of particles coming from one block to the one it's linked to, but I'm not sure how to proceed with that. I'm guessing it would have something to do with the velocity numbers (vx, vy, vz), but that would require math that I'm not good at so that's why I'm asking for help.
if anyone could help with this, that'd be appreciated.