So the first poster post a nickname and then the following poster for provide a full name for that nickname. Then they would add a new nickname for the next poster.
For example:
Poster 1#
[name_u]Alex[/name_u]
Poster 2#
[name_m]Alexander[/name_m]
[name_f]Maddy[/name_f]
Etc, etc.
First nickname: [name_f]Lily[/name_f]