\sblngboxcfg{1ex}
\indvdldef{youngSybil}{Lady Sybil}
\indvdldef{youngEdith}{Lady Edith}
\indvdldef{youngMary}{Lady Mary}
\sblngdef{youngSis}{youngMary,youngEdith,youngSybil}
\fbox{\usebox{\youngSis}}
\hfill
%
\makeatletter
\let\nameuse=\@nameuse
\makeatother
\newcommand{\boxsz}[1]{%
  \texttt{\textbackslash#1} & \nameuse{#1}\\%
}
\newcommand{\tblA}{%
  \begin{tabular}{l|l}%
    \boxsz{youngSisnameCY}%
    \boxsz{youngSisyoungMarynameCY}%
    \boxsz{youngSisyoungEdithnameCY}%
    \boxsz{youngSisyoungSybilnameCY}%
  \end{tabular}%
}
\par
\bigskip
\hfill\tblA