Let\'s say I have a project with this structure:
MyLibrary\\
MyLibrary.sln
MyLibrary.Core\\
MyLibrary.Core.csproj
MyLibrary.Extensions\\
MyLibr
I recently published a solution for this...
My solution enables automatic creation of NuGet packages when you build the solution where each package can contain multiple assemblies, references to both external NuGets and NuGets created during the same build and even include the source code for debugging.
In your case, all you will need to do is add a new class library project to your solution, reference the projects you want to package, then add a post build event.
You can find an article with a walk-through guide here and the source code + binary here.