Best bet is to carefully understand the Depth of Field that your chosen settings will provide, and position your subjects accordingly, or change your settings.
With the setup you provided, if your subjects are 5 feet away, you have a total of .32 feet or about 4 inches of depth that will be in focus. Therefore, your subjects need to be equal distance from the lens, to be in focus. This will require measurements to be sure of focus most likely, therefore, you may want to consider changing your set up to be more favorable to ensuring sharpness of focus:
If you stand 10 feet away, you have 1.3 feet of area in focus.
Better yet, if you change your aperture to f/8, you have about 1.5
feet of focal depth, so any offset distance between two side-by-side
subjects will be minor, and both will likely be in focus.
To calculate these distances, refer to the excellent, and always helpful DOF Master