You'd have to go the Air Native Extension(ANE) route. Either create one ANE solution for iOS and Android each, or one ANE that abtracts the functionality into one solution. How to launch app A from app B on Android is not the same as on iOS. See this answer in SO.
To implement it on Android, you'd wraps the native Android Java solution in a ANE. The native Java code uses the package name of app B to launch app B from app A:
Intent intent = getPackageManager().getLaunchIntentForPackage("com.yourdoman.yourapp");
startActivity(intent);
Here is a video tutorial on how to launch an Activity through an ANE which you can build on to create your ANE. You'd have to tailor the solution to launch by domain instead of Activity.