For me, it depends upon the desired result. What are you looking to achieve in this situation? Do you want the background to remain white or have it darkened to grey? Do you want them so close that shadows appear on the background or not?
If they are so close (like just one foot away), there isn't a whole lot of override you can accomplish. You could try lighting them from the side at 90-degrees. Joel Grimes does that with what he calls Rembrandt Cross Lighting. The light is 90-degrees to their body but is placed in front of them with just the back edge of the light hitting them. A reflector can be used on the opposite side. That would eliminate a lot of backdrop shadows caused by the strobes, but ambient light might still create shadows on the background.
However, with Photoshop you can extract them from the white background and put the subjects into a different background. But what do you want the outcome to be?