Well, I'm glad you're going to try to remove them with animal control/ranger or something first. I followed a male fox carrying a rabbit back to it's den which held a female and pups awhile back. The den was located under an old barn near a house. I went and actually spoke to the people about the foxes out of concern. They let them live there. I really don't think you have anything to worry about, however, if it does come down to your only choice being to shoot or poison them, please, please, let me know and I'll drive them out myself, with my dogs if need be. I'll even bring the beer (if you drink) and the hilarity.
Also, they make traps that go over groundhog holes, but I do know shooting them is going to be cheaper.