Upload & Sell: Off
For those of you with this problem, I offer a suggestion.
Take a large dished saucer or small plate and place it, filled with sugar water and bit of honey, on or near the ground about 10-15 feet from the hummer feeders, preferably in the shade.
Bees and yellowjackets will generally discover this in a couple of hours and then swarm it, prefering to feed from the open saucer. Hummers will normally leave it alone, as it does not match their normal feeding style. I use this technique during the spring and fall ruby throat migrations here in north texas and it seems to work quite well as a means of diverting the bees and wasps from the feeders.