Heck YES
Just decide on what you want to translate on the Arduino side. You could send "Toot" from PC to Arduino and have the Arduino board blow the whistle.
Or you could send "toot toot" for two toots.
Or toot could == 2, then you could send the single character "2" to blow the whistle.
Essentially, the Arduino must parse each command, the execute on that serial input translation.
Rough idea of power from a very old rainy day project of mine: