To make a long story short, no! They somehow communicate to each other where all the goodies are at. Bees are very efficient, so, if there's plenty of nectar straight out the hive at a mile and a half, and they find (they will) better nectar sources to the left of the hive at 1/2 mile, they will work that instead...
But, remember, they are efficient. So, why aren't they working the dandelions 2 feet from the hive? Because they know what is more efficient. They know that they can go out 1/2 mile and load themselves down fast and easy by going to a particular spot.
Besides that, I'm sure they have already worked the dandelions in front of the hive numerous times!