making multigraphs
 

hello, i am attempting to make what in math is called a multigraph.

this is a graph which can have multiple edges that start and end at the same vertices. it can also have loops where an edge starts and ends at the same vertex. the first picture on the [URL="http://en.wikipedia.org/wiki/Multigraph"]wikipedia (multigraph)[/URL] article shows a perfect example.

i can get this kind of graph to display (the edges don't overlap each other) if i use multiple magnets and such, generally it's a lot of work for something i could just draw and scan faster. is there a way to use omnigraffle's fast and neat graph generation for multigraphs instead of simple graphs?

followup
 

it has occurred to me that i might be able to get the effect i want i i could draw lines between shapes that did not create a relationship in the outline.

is there a way to put down a line which will keep itself attached to the shapes no matter what configuration they go into, that also does not suggest a relationship that the diagram layout will use?