Dichroic Mirror in Blender Using Pariticle System for Laser Beams?

Hello,

I am a new blender user and model a setup up of laser beams. I have managed to create beams using the particle system with the blender render (https://www.youtube.com/watch?v=yLHJR1MOPYs); cycles does not show me the beam for some reason.

The next step was to make mirrors to deflect the beam, similar to: http://www.creativeapplications.net/wp-content/uploads/2014/04/3LCD_projector.png In this figure, one can see two Dichroic mirrors which deflect the incident beam which consists of multiple colinear beams. I would like to reproduce this with blender such that I have a mirror, that transmits particle stream 1 but reflects particle stream 2.

Here is my attempt: https://i.imgur.com/MY8ky7p.png In this figure, I have the blue particle stream overlapping spatially between those both mirrors with a green and a red particle stream. Now, I want to transmit the green and the red beam through the second mirror but the blue should be reflected at this mirror (as it does for the first one). So far I only managed to make the mirror semi-transparent.

Does anyone know how to do that? My intuition tells me that I should be able set collision for beam 1/2 on/off somewhere?

Cheers
NoLimits