Particles colliding when they shouldn't

I have used the Layer Collision Matrix from the Physics Settings to make a particular collider (for clarity's sake, let's call it Colin the Collider :D) collide with nothing but one of the Game Objects. Colin has its own layer, the object it is supposed to collide with has a different layer.

Then, unrelated to this, I have a particle system in the default layer. For some reason, the particles from the system collide with Colin.

How can I prevent this?

make a new layer called particles, assign that layer to your particles game object and in the layer collision matrix uncheck where Colin's layer and the particle layer intersect.

OK, it's fixed. I had to go to the Wold Particle Collider Component of my Particle System and uncheck the relevant layers in the 'Collides With' parameter. Funny how it's independent from the collision matrix...