From the Help
“As with any Deformer, this one can be made a Child of an object in order to deform that object. Jiggle differs from other Deformers in that it does not affect all objects with which it is grouped below a Parent Object. This is due to the fact that Jiggle must trace the movement of all points it affects. If you want the Jiggle Deformer to affect multiple objects, all objects must be assigned their own Deformer.”
C4D Help is contextual, just hover the mouse over a parameter in the object manager and it will take you to the help for whatever you are over