making objects without collision

[cesm20]

Yesterday i was trying to make a object in a track not having a colision model (you know, a flag object or bushes so that the car goes trough them without smashing on them) but i was unable to make that. I tried making it as a noncar without bounding boxes, but i have too many objects like this, and the noncars limit in carma2 is 43, so i have to find another solution.

So i had the idea of trying to use the prefix \ or ! in the object name in pt2 and for my big surprise, this indeed works in objects too, just like in textures ! BUT after preprocessing it doesn't work anymore... any sugestion in how to make this work in a preprocessed track ?

The only alternative i had was making all materials of those objects with the \ or ! prefix, and it worked, the object is not solid anymore even in preprocessed tracks, but i would like to know if there is a alternative since like this if the objects materials are used in the rest of the track i have to duplicate them without having that prefix...