Parameter
Drag & drop the name of the particle group you want the particles to be assigned to from the Thinking Particles Settings into the PGroup box.
A Boole value of True switches the node on; a value of False switches it off.
Connect the stream of particles you want to assign to the group to this port. For example, you can connect a PStorm node to this port to collect all the particles that are output by the PStorm node.