Heavily inspired by the many, many, sibsets you know games. This works just like this, but instead of a sibset you actually know, add some names that you think would make a perfect sibset with one of the names in the previous one. Middles are optional - if you want, you can add middles that you think would be suitable to the names from the previous set.
example ~
poster one:
[name_f]Dorothy[/name_f], [name_f]Lucille[/name_f], and [name_f]Mabel[/name_f]
poster two:
[name_f]Lucille[/name_f], [name_f]Helena[/name_f], and [name_m]Oscar[/name_m]
poster three:
[name_m]Oscar[/name_m] and [name_u]Jasper[/name_u]
starting fake sibset ~
[name_u]Sparrow[/name_u], [name_f]Lilac[/name_f], [name_f]Bronte[/name_f], and [name_f]Anwen[/name_f]