I do not want fix SMS rate in playsms

example I have 5(ABCDEF) users who sending sms from playsms user A should pay 50 paisa and user B should pay 60 paisa and user C should pay 70 paisa and so on. How can I define in playsms.
please reply as soon as.

You canĀ“t. But, When you charge your custumers, you can change $ amount in SMS units, aplying your conversion rate for each one