xpInherit General tab.
Checking this box enables the xpInherit modifier.
This first scene shows the particles from the target xpEmitter.
In this animation, a second xpEmitter has been added, with particles from the inherit emitter.
Finally, you can see the effect when xpInherit is enabled, with particles from the second emitter inheriting the defined parameters from the first.
Set at Independent, by default.
You can change this to Action-Controlled.
In this mode, particles will be affected if they come into the field of effect of the modifier.
When in the Action-Controlled setting, the modifier will only act on a particle when told to do so by an action.
Until that point, the particle will not be affected, but once activated for a particular particle, the modifier will influence the particle - that is, it will play back the history.