Yes, just sub out some of the 2 row with some smoked malt of your choice. As ynotbrusum says, it will depend on your tolerance of smoke level how much smoked malt you add. I've gone as far as 50% of the grain bill before (smoked myself over apple wood - very smoky).
Also as was mentioned, older rauchmalt might not be very smoky. Because of that I prefer to smoke my own malt. It's not too difficult. I have a small square frame with a screen I built that fits on my smoker. It can handle about a pound at a time but it only takes 10-15 minutes or so to get it plenty smoky so doing several pounds in an hour or two is no problem.