% Group expands the last row so captions clear the outline.
% One callout hangs off the finished band.
\documentclass[border=8pt]{standalone}
\usepackage[en]{superfig}

\sfsetrole{q}{sfTeal}
\sfsetrole{w}{sfOrange}

\begin{document}
\begin{tikzpicture}
\sfstage{S}{composite plus aside}
\sfrow{R1}{12mm}
  \sfnode[role=q]{A}{$A$}{14mm}{10mm}
  \sfconn{e1}{}
  \sfnode[role=q]{B}{$B$}{14mm}{10mm}
  \sfgap{\sflinklen}
  \sfnode[role=w]{C}{$C$}{14mm}{10mm}
\sfrowend
\sfgroup[role=q]{G}{(A)(B)}{}
\sfarrow{G.east}{C.west}
\sflane{R1}
\sfcaption{G}{$AB$}{one composite}
\sfcaption{C}{$C$}{consumer}
\sfcallout{N1}{32mm}{R1}{aside}{The card hangs off the band, not off $C$.}
\sfbbox{all}
\sftopformula{F}{$C = f(AB)$}
\sfmeaningbox{mb}{108mm}{all}
  {a group is a real composite}
  {pair $AB$, consumer $C$}
  {captions sit below the outline because the group refits the row}
\end{tikzpicture}
\end{document}