How can I make my Android Library Plugin (.aar) resources folder accessible so that anyone using it can easily modify or include their own drawables resources?

I'm not very familiar with android development. I would want to create an android library (.aar) to use in any Unity project, but what I would want is use a default resources folder that any other development can override or set his own resource folder.

I'm creating a notifications plugin, what I would want is establish a default icon, that I set in resources drawable, but I would want to allow my developers can use their own icon.

How can I make my resources folder accessible so that anyone using my android library (.aar) can easily modify or include your own drawables resources?

Is there any way that I can set my custom resources folder aside my android library (.aar) file in Unity? Something like this?:

I'm using Android Studio 2.2 and Unity 5.4.1 Personal Edition