Material blending/alpha clamping

Basically, my problem is that I have a ribbon particle that I want to be at a certain opacity. However, since the ribbon is just spawning a bunch of particles on top of each other, there is never any opacity because they’re blending together. So is there a way to give a material blending parameters, in the same way you might set a blending function in OpenGL? Or is there some other option I’m unaware of to get this to work?

Anyone know?