Hi,
From my understanding using layers can help with performance, but as you don't mind using a 2nd raycast to fix your issue, I will assume that this is not your goal.
So then I can suggest that you could just remove the intractable objects from the layer and put a unique tag on them instead. Then in the raycast settings you could save the object and use 'game object compare tag' action.
https://hutonggames.fogbugz.com/default.asp?W218I would set it up like this: FSM 1: just have one state that sends the raycast and saves the hit game object to a global variable.
FSM2: state1: compare tag of the global game on object variable that you set in FSM1. If it is interactable go to state2
State2: compare tag every frame (and send back to state 1 if the object is no longer intractable). And add whatever actions you have for interacting.
You could also do it differently and simply add the walls to the same layer as intractable objects, while still tagging the interactable objects, then just use a tag compare to distinguish between walls and interactable objects.
This is all assuming that you haven't tagged or layered any of the objects already. But some version of this may work for you, just might need to play around with it.
Hope this helps and good luck with it!