\begin{idxblock}{C}
  \idxentry{
                \indextitle{}{Caa}
            }{
                \hyperlink{song1-3.2}{3}
            }  \idxentry{
                \indextitle{}{Çab}
            }{
                \hyperlink{song1-2.2}{2}
            }  \idxentry{
                \indextitle{}{Cac}
            }{
                \hyperlink{song1-4.2}{4}
            }
\end{idxblock}
\begin{idxblock}{M}
  \idxentry{
                \indextitle{}{My song}
            }{
                \hyperlink{song1-1.2}{1}
            }
\end{idxblock}