Make only one object unable to collide with tagged objects

I need to make it so that only one object is effected by the collider of objects under a tag.
In other words, the main player, for example, cannot pass a wall, but every other gameobject in the scene can.

I am using this code for now and will change it to work with tags later:

var object1 : GameObject;
var object2 : GameObject;

function Start () {
    Physics.IgnoreCollision(object1.collider, object2.collider);

This script doest the exact opposite, of course, letting one object pass through another while no other object can.
But is there a function that is the opposite of Physics.IgnoreCollision that the opposite happens?
I am a little new to scripting so I am probably missing something obvious…

You can create 3 new layers: Terrain, PLayer and BlockPlayer. Move the terrain to Terrain, the wall to BlockPlayer and the player to PLayer. In the Physics Manager (Edit/Project Settings/Physics) uncheck the crossing of BlockPlayer with Default, and voilá: everything but the player passes through the objects placed in the BlockPlayer layer.

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What this does is to avoid collisions between the Default layer (where all objects are placed by default, as its name suggests) and the BlockPlayer layer.

NOTE: The Terrain layer may be unnecessary: it was created just to avoid that BlockPlayer objects fall through the terrain case they are rigidbodies. If you don’t need to add rigidbodies to BlockPlayer objects, you don’t need the Terrain layer as well.