Physics Masks not working

i have an aircraft flight setup, where the plane is surrounded with a rather large sphere collider which is used to collide with walls. Third person like. Means I see my plane in front.

Now I want to add collectables, but the plane collider is to large.

so I added another smaller collider with rigid body inside my plane, but than everything went haywire. So I moved it out of the hierarchy and scripted it to follow my aircraft. That improved. However, I only want to have this little collider to collider to collide with collectables, NOT with walls.

And visa versa, the big collider shall only collide with walls but not with collectables.

I found a forum topic which leads to:

However I cannot get my small collider to work.

Whats the deal? Do I need to apply the physicsLayer script also to walls? is there no standard group?

the image above shall illustrate the problem. Red must collide which each other, ignoring green.

Green shall only collide with green.

The small green dot is the collider which is following the player.

as a side note:

Walls have a collider and rigidly component set to static.
The large plane collider has a collider and a dynamic rigid body.
The collectable only has a collider, thus it is a trigger.

Basically, yes. Masks and layers are not officially supported by the engine so the default setup doesn’t work with other physics objects that have additional groups.