\begin{idxblock}{A}
  \idxentry{
                \indexauthor{}{Aba}
            }{
                \hyperlink{song1-4.2}{4}
            }  \idxentry{
                \indexauthor{}{Äbc}
            }{
                \hyperlink{song1-2.2}{2}
            }  \idxentry{
                \indexauthor{}{Abd}
            }{
                \hyperlink{song1-3.2}{3}
            }
\end{idxblock}
\begin{idxblock}{J}
  \idxentry{
                \indexauthor{}{Jack}
            }{
                \hyperlink{song1-1.2}{1}
            }  \idxentry{
                \indexauthor{}{Johns}
            }{
                \hyperlink{song1-1.2}{1}
            }
\end{idxblock}