Well, I checked on the girls this afternoon. The really weak hive with all the yellow jacket issues seems to be doing a little better since we screened the bottom entrance and put out some wasp traps. I still saw wasps around the hive, but they seemed to be getting chased out pretty well.
The other two hives look pretty strong right now. They were kicking serious wasp butt - and there weren't near as many wasp as in the past.
I really hope these girls strengthen up a bit. Winter is straight ahead. We'll open all the hives and see how they are doing with the sugar water.