Using palette pointWeight COMP to control birth locations of particlesGPU?

Is there a way to use the output of a pointWeight COMP to control from which source pixels/locations the particleGPU COMP emits particles? Just stuffing it into the particleSource alpha channel
does not seem to do it. See attached file particles.toe (499.3 KB)

And a second question. In the same file you can see that every second there is a trigger that accelerates the movement of the point cloud through the noisefield. Now during each trigger, I’d like to emit particles in the direction of their source points movement, but only from the points that move quickly. Any ideas how to achieve this ?