Map Help: Two Object properties?

Hey, Its me again - Begging Facepunch for mapping help.
So let me start;
My MiP is a Mario Themed deathrun.

From the beginning you are being chased by a Bullet (Bullet Bill), the Bullet is set to a trigger_hurt meaning you can stop too long or you’ll die.
Bullet bill has to be able to go through other brushes, entities ect…, but not players, How can I do that?

so, is the bullet, the entire bullet, a brush that you tied to a trigger_hurt, or is it a prop/entity with a trigger_hurt parented to it? If there’s some universal way to do it I’m not aware of, sorry, but I believe there’d be separate methods for entities and brush entities.

Make the bullet bill have collisions off but just have the trigger hurt kill them (assuming it’s parented to the bill).