Android Studio how to package single AAR from multiple library projects?

I am building android library project, which has a dependency on another internal library project.

I am wondering if there is a way to package a single AAR library, which already contains internal library inside it. I would like to share only 1 AAR library package to my application developers.

This is how my build.gradle files look currently, but currently they produce separate AAR files and both needs to be included in Application's build.gradle. As application is being built by another company, we need to share the final AAR file with them and not the complete library projects.

----- internalLib -------->>>>>>>>>>

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.7.+'
    }
}
apply plugin: 'android-library'

repositories {
    mavenCentral()
}

android {
    compileSdkVersion 18
    buildToolsVersion '18.1.1'
}

dependencies {
    compile 'com.android.support:support-v4:18.0.0'
}

----- externalLib --------

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.7.+'
    }
}
apply plugin: 'android-library'

repositories {
    mavenCentral()
}

android {
    compileSdkVersion 18
    buildToolsVersion '18.1.1'
}

dependencies {
    compile 'com.android.support:support-v4:18.0.0'
    compile project(':internalLib')
}