Share your experience!
I can set a default ringtone but set specific tones for individual contacts. My old Samsung phone also allowed this with text notification tones. Work message could be one sound while family and friends were another. Is there anything like that for the xperia?
I think what you need is a 3rd party app from google play.
Google Messaging it's a great option
https://play.google.com/store/apps/details?id=com.google.android.apps.messaging&hl=en