You can use a higher aperture, say f8 isn, but make sure they're far away from the background. And FYI... Bokeh. Brokaw used to do the nightly news, haha. He was a great man though.
To get the best bokeh, shoot with a large aperature (small number), large focal length (zoomed in), from close range (camera close to subject), and subject far from the background. Larger depth of field would happen by closing the aperature, but you would have to increase some of the other factors to keep the same bokeh in the background.
The best way would be to take a test shot and carefully look at it, make changes, another test, look again. Once the settings are to your liking, then you start the real photo session. A lot simpler with digital than it was with film. But we did have polaroids...