Not a stupid question at all. You can't do this with your stock ECU and MAF setup, because the MAF has to measure "all" the air going into the motor, including the idle air.
However, it's done quite often on 2JZ Supras that have been singled and equipped with a standalone ECU and a MAP setup. K&M make a nice little breather filter that fits fine on the Toyota IACV inlet.