When it comes to movement in group photos, it’s best done with groups no larger than 6 – 8. Any larger and things start to become a bit more chaotic and may actually not look good at all.
Regardless of how many people you have in your group photo, don’t forget to be encouraging and to compliment the group once you’re done. It makes a world of a difference when the people hear you say “Damn, you guys look great!”. They start to genuinely have a good time in front of your camera.
Finally, try and convince your couple to do the group photos before your couple shoot as this could push your couple shoot later on into the afternoon / evening which is, obviously, a much nicer time to be taking their photos.