title: How to assign the same style to a group of edges?
body: <p>I've got a graph that I want graphviz to layout and visualize for me. The graph has 122 edges and 123 nodes. The edges are of 4 different kinds and I want them to be visually distinguishable. However I've not yet decided what would be the best way of doing that, I'd like to play around with the dials a bit. </p>
  
  <p>Unfortunately I do not see anything like a "class" or "stylesheet" attribute for edges. I can only set visual attributes individually for every edge (lots of repetition). Perhaps I've missed something? Is there maybe some way after all to add edges to 4 different groups and then style the groups, not each edge individually?</p>