How to assign a specific collider of the object to OnTriggerEnter/Stay/Exit2D?

How can I make it inside of a OnTriggerEnter/Stay/Exit function that the whole thing works for only one collider on the object the script is attached to? So that when anything is colliding with the chosen collider it triggers. Any ideas?

Use GameObject.CompareTag() and use the tag for the object you specifically want collisions to happen for.

Further reading: Unity - Scripting API: GameObject.CompareTag