Thanks for the information, Andreas.
Please have a look at the file and screen capture (download the screen capture as well, it is better to watch this way)
https://www.amazon.com/clouddrive/share/eOEmJ0dqxMGRlqFFBgW7SAQVSqyq2tFgRybY5TdLplA
The idea is to use capsules as a way to define the space needed for each Sphere-Pair to have an unobstructed path to connect. This is shown in the first half of the screen capture. It produces a polygon object, to store that information.
The second part is about the travel of the sphere to the other one. It is done with a Blend in one Cloner Object and adjusted with a Plain Effector. This set up is then placed under another Cloner Object to get the positions of the “Volume” based clones.
With a Field (falloff) the Modify Clones effect can be animated precisely in time and space.
Simplified Alternative:
A simplified version would just double a single Sphere set up by copy and paste the Cloner Object. Then use a Random Effector to move the new spheres away from their current positions. With a Falloff in the Random Effector, the move to the original place can be established. Which gives the effect as if spheres move towards the initial spheres.
Screen capture and scene file
https://www.amazon.com/clouddrive/share/RrSVlLe1p3flsVSEsfuriLoqnH7Kd5MEAmvKPnmKJwG
Let me know if there is any other question, I’m happy to look into it.
All the best