C++ Graph upgrade to Multigraph

I have a working code in which I store routes between cities in a Graph (using a standard Sedgewick implementation), but I would also like to store several Edges between Vertices because each edge contains information regarding whether the route is by bus, or by train or by plane. Simply put, the should represent that you can get from A to B by different ways, and this should be represented. I need someone to update my code accordingly, its just a few lines of code (graph class, graph iterator class, and a depth first search algorithm).