It's a special applet for 300iq and up
If
New SMS received matches search
This Trigger fires every time you receive an SMS on your Android device that matches a search you specify.
Then
Play a specific song
This Action will play a song you specify on your Android device. The music played depends on your device and setup. Depending on your version of Android, playback may not start automatically.
Explore more great ways to automate Android SMS and Android Device