将不同的Android项目连接到现有的Google-Endpoints后端

I am working on an Android project that needs three versions of the same application (for example: Admin version, User version, Custom version). I have already created a Google-App-Engine endpoints backend in the User version of the app. I have to start working on the other two versions now and I want to connect these two versions to the backend I created in the User version. I have tried finding the answer to this on the internet but I haven't been successful in doing so. I believe it is possible to connect the other versions of the app to the backend by importing the endpoint libraries from the cloud into the android projects somehow but I haven't been able to find a way to do so yet. I did come across a way to import an existing module in the Android project but if I do that, then any time when I make changes to the backend in the "User" version, I will have to re-import the module in other versions of the app. I am so lost and confused.I am working on an Android project that needs t