How can i make only some Raycasts hit triggers

I’m sure there is an easy fix for this but i have no idea what it is, basically i use Raycasting for picking up items using triggers, and a separate Raycast for telling my game where to shoot.

The problem is that when Instantiating a decal, the shooter raycast hits the triggers and the decal hovers over some objects (sorry for the bad explanation, see picture below).
Can i either make some Raycasts ignore triggers but not others or toggle the ‘Raycasts hit trigger’ option in physics settings via C#.

Thanks for any help.

Screenshot: http://s10.postimg.org/uvrmu86rt/Trigger_Issue.png

you should make a layerMask and use it in your raycast like below , make a layer for objects you want to use them to trigger and say to use that layer on your raycast

(if new layer is layer 8)

int layerMask = 1 << 8;

    if (Physics.Raycast (transform.position, Vector3.forward, Mathf.Infinity, layerMask)