\begin{theindex}
  \providecommand*\lettergroupDefault[1]{}
  \providecommand*\lettergroup[1]{%
      \par\textbf{#1}\par
      \nopagebreak
  }

  \lettergroup{س}
  \item سلام, \hyperpage{1}

  \indexspace

  \lettergroup{ف}
  \item فارسی, \hyperpage{9}

  \indexspace

  \lettergroup{گ}
  \item گراف, \hyperpage{9}

\end{theindex}
