Grouped multi-column nomenclature

Not sure this is the best solution, but still...

% arara: pdflatex
% arara: nomencl
% arara: pdflatex
\documentclass{article}
\usepackage{nomencl}
\usepackage{multicol}
\makenomenclature

\makeatletter
\newif\if@nomlist

\newcommand*\nomlist{%
  \@nomlisttrue
  \list{}{%
    \labelwidth\nom@tempdim
    \leftmargin\labelwidth
    \advance\leftmargin\labelsep
    \itemsep\nomitemsep
    \let\makelabel\nomlabel}}

\renewcommand*\thenomenclature{%
  \@ifundefined{chapter}%
    {\section*{\nomname}\if@intoc\addcontentsline{toc}{section}{\nomname}\fi}%
    {\chapter*{\nomname}\if@intoc\addcontentsline{toc}{chapter}{\nomname}\fi}%
  \nompreamble
  \@nomlistfalse
}

\renewcommand\nomgroup[1]{%
  \if@nomlist\endlist\end{multicols}\fi
  \ifx#1A\relax
    \def\nomgroupname{Latin}%
  \else
    \ifx#1B\relax
      \def\nomgroupname{Greek}%
    \else
      \def\nomgroupname{Other}%
    \fi
  \fi
  \begin{multicols}{2}[\noindent\large\textbf{\textsf{\nomgroupname}}]
  \nomlist
}

\renewcommand*\nompreamble{}
\renewcommand*\nompostamble{\end{multicols}}
\makeatother

\usepackage{lipsum}
\begin{document}
\lipsum[1-2]

\nomenclature[A]{a}{1}%
\nomenclature[A]{b}{2}%
\nomenclature[A]{c}{3}%
\nomenclature[A]{d}{4}%
\nomenclature[A]{e}{5}%
\nomenclature[A]{f}{6}%
\nomenclature[A]{g}{7}%
\nomenclature[A]{h}{8}%
\nomenclature[A]{i}{9}%
\nomenclature[A]{j}{10}%
\nomenclature[A]{k}{11}%
\nomenclature[A]{l}{12}%

\nomenclature[B]{$\alpha$}{1}%
\nomenclature[B]{$\beta$}{2}%
\nomenclature[B]{$\gamma$}{3}%

\printnomenclature
\end{document}