How to make a force field concentrate only on a specified area? For example if I use 3 different object emitting particles, I only want 1 of them to get affected by the force field.



I tried adjusting the area to be concentrated, but the force field affects everything which is in the same layer.



These are the settings that I’ve done to adjust where the force field should take effect.
You can set the Effector Group to limit the force fields which can affect a given particle system:


Add an empty (or really anything that's not a force field)
With the empty selected, create a group (&#9096; CtrlG)
Specify this group as the Effector group for the systems which you do not want to be affected by any force fields:


Optionally delete the empty.


Result: