Yes you can use the multiple package in android, Only you have to play with access modifiers within your application, so that your one package class or object can communicate with other package class when desired.
Java provide different access modifiers:
- Visible to the package. the default. No modifiers are needed.
Visible to the class only (private).
Visible to the world (public).
Visible to the package and all subclasses (protected).
For more read here
Edited:
You can define the main package(Application main package) and other package into your manifest like this:
<manifest package="com.example.mainPackage">
<application . . .>
<activity android:name=".packageOne.ActivityOne" . . . />
<activity android:name=".packageTwo.ActivityTwo" . . . />
<activity android:name=".packageThree.ActivityThree" . . . />
</application>
</manifest>