Is there a way to have a particle collision detect the particle shape rather than the particle itself.

Here is the scenario: I want to have a particle (using shape instance) emit and then when the actual mesh of the particle passes other points in the scene, a new particle is emitted from that intersection.

Imagine a sphere (for easy understanding) expanding slowly and there are points in the scene that when the spere touches, they emit a sphere of their own.

I have this setup and sort of working but I have had to place a deflector in the scene at the wrong place to get the intersection working since the collision spawn only seems to work on the actual small particle and not the shape instance geometry.

What I want is to be able to modify only the master particle speed and then the collision detection does the rest instead of having to manually adjust loads of particle births everytime I change the master particle speed.

Hope this makes sense to someone.