The problem ... shooting this group without the wide white background left the photog with few options from the start. The narrow white meant that to keep them on the background he had to cram them together.
On the left
 | The two people in the second row are just inches too close to the center. By moving them 2 - 3 inches out away from each other, you would make the photo work. As it is, they are to close and covering up the people behind them too much. |
| They also don't create compositional triangles ... instead the are more vertical lines between the heads. |
On the right
| Again they are too vertical ... move the two blocks 3 - 5 inches out (each one totaling 10 inches) and you would have them more evenly spaced and the faces the correct distance away (all even and no one above or next to another) |
| Also, on the right the background separating the two subjects from each other creates two separate groupings ... in all portraits, everyone should be connected to each other in some way (even if it's only overlaping) |
| Finally, the guy sitting needs his feet adjusted ... he should be turned slightly more towards the center of the group. |
In these groupings, there is even spacing (except the woman who is too much directly under her son ... she needs to go 3 inches to our right) I feel they are a little bunched up in the full length but presto, on the left as a closer shot with the long lens all of a sudden the grouping works better.
I always do a second grouping ... and I'm not a thrilled with this one, because the colors don't balance. The spacing however is much better with even spacing between all the heads and no one directly above or below another.
The formal rule is that:
No one is directly above another or beside another. Also, for the triangle to work, each person's eyes should match with the person next to them's mouth. (going from left to right, the son's eyes line up with the mom's mouth ... her eyes line up with her husbands mouth ... the daughter's eyes should match with her dad's mouth ... and the girl seated's eyes should match with her sisters)