First off, do you have flowers that are attracting the bees. It might be something to look at.
Some folks confuse yellow jackets with paper wasps. Having some pest control experience, I may be able to tell the difference when others aren't able to. If the wasps are large, you probably have paper wasps. These are the ones that build open comb nests under your eaves and may have up to 50 or 60 adults on the nest in late summer. Just look around for nests in the general area. Raid is the answer. Soak the nest good after dark. However, if the wasps are small, bright yellow and black, and do a lot of hovering in flight, you have true yellow jackets and read on.
Yellow jackets...totally different story here. Yellow jackets (not paper wasps), live in colonies of up to 5000 individuals. They can live in the ground or in aerial nests. With these guys (actually, it's the gals that sting), you should observe their flight patterns. If you have a lot of yellow jackets, odds are, there is a nest close by. Watch them fly and determine which direction they are coming from. Carefully and avoiding getting in their way, try to follow them back to their origin. If you can locate where they are coming from such as a hole in the ground or a hollow tree, you can then hire an exterminator to get rid of them for you. Yellow jackets are dangerous, venomous insects and their nests are not something that a person can generally kill off with cans of Raid. To safely eliminate them requires special chemicals (Drione dust and duster) and equipment (fully encapsulated bee suit).
For what it's worth, the little traps that you see for sale do little to help with true yellow jackets and may serve to simply attract more to the area. An exterminator is the best person to deal with them. And tell your kids to not splash or swat at them. I am highly allergic to all hymenoptera (insects that sting) and have learned the hard way. Of course, kids tend to panic and this is understandable. It is best to explain to them that when they are away from their nest, they are not on the defensive and are simply looking for a drink. They will go about their business after they get their water.