Android : Gradle script to replace classes and function names

This is not a code question per-se. I want to create a gradle script to change classes, functions and assets (such as XML names etc.) according to a flag raised . for example , lets say I have a class or activity named A if a "regular release" flag is on , I want to keep the name as A but if a "specific release" flag is on , the class name should change to "SpecificA".

I read some of gradle documentation yet I couldn't find a script for that, any ideas?