An Umbraco Visual Studio solution with a single project acting as the core code base that is to be deployed to a number of websites. Each website will have it's own config file transformations, CSS, JS and View overrides. When the core code base is updated, this will need to be deployed to all of the websites.
I've toyed with the idea of separate repositories per website installing the core code base via a private NuGet package, but thought that might be quite time consuming as the number of websites grow, having to update each individual repository.
The ideally scenario in my head would be for the build server/client, GoCD, to somehow merge the core code base with each individual website and deploy accordingly.
Looking for any suggestions on how to approach this.