I'm having trouble disengaging a group from combat, even after they leave the room in which the combat started. Anyone know how to do that?

If you run for the hills but the enemy is still near by (and they still have creatures on the initiative list), then you're still stuck in combat.

If you manage to get away and the creatures are all dead or gone off your initiative list, then you might be able to hit the "Combat Mode" key to get out of combat mode (I can't remember it off the top of my head -- possibly C? But you should be able to find it in your options menu).

I don't know if I was ever able to run away, so you may just be stuck in combat until you kill all the baddies.

You could probably use Web or something similar to hold the enemies in place, while you run out of their sight.

You have to select "flee combat" from radial menu