Donut ring collider

I have a game object that is the shape of a ring. I want to be able to teleport the player when I collide with this object, however I cant find a way to make just the ring a collider. Think of the ring as a boundary. I have tried using every kind of collider I can find. It either doest work or it make the inside of the ring a collider so you just get pushed out when you spawn inside the ring. I want to know how I can make just the ring itself a collider. Thanks in advance! Henry