I'm sorry about the unexpected house guests...always a fun thing!
Some questions for you -- what exactly are you doing to DR throughout their stay? I'm curious about what strategies you might be using, not only with H, but with them as well.
For instance, it occurs to me that you could do a lot of "acting-as-ifs" in this sitch -- acting as if all of your previous encounters with them were enjoyable and pleasant.
You could probably do some 180's here too. Other than detaching and not getting sucked into their drama, as you said, what would be some real 180's you could exhibit?