Correctness of "alongside" vs "along with"

Solution 1:

Alongside implies a physical location. For instance, "right next to."

1 : along the side : in parallel position
2 : at the side : close by · a guard with a prisoner alongside

Along with means in conjunction with, or part of a group.

1 : in addition to (something or someone) · a plane carrying heavy radar equipment along with full fuel tanks

2 : together with (something or someone) · A bill came along with the merchandise. · He worked along with several colleagues to finish on time.

In the example of the wedding invitation, in order for four people to have been alongside each other, they would have to have been physically huddled in a group, almost touching each other, when writing the invitation . . .