I don't think it'll take that much processing power
firring raycasts approximately every ten milliseconds?
I have seen something that is not exactly what you search for but might prove useful to accomplish what you want to do.EDIT:Got it, here take this.If you use something like zone events and zone bricks you can let it shoot a relay from a player in a certain zone.Then event the brick that has to be looked at to do something onRelay and tadaa!
OnInZone - Player - castRelay[(number of bricks between the zone brick and the brick to be looked at (aprox))]
onRelay - dosomething
>onPlayerlook >Player >Kill