I haven't heard about cotoneaster, I don't know how you can keep your bees away from it in an urban or semi-urban or even rural environment, given their foraging habits.
However, we did cut out a cotoneaster from our yard , because they are a noxious weed, and birds spread them into the bush by eating the berries . . . .like darned privet (large or small), it actually is good bee foraging, but still a noxious weed in Australia, so if you can, get rid of them.