How to write a LaTeX title with multiple authors and several of them belong to the same organization

Some LaTeX document classes (especially academic and journal-provided ones) provide commands by default that make it easier to describe multiple organizations, but the jsarticle class doesn't seem to have that function, so I think it's faster to use external packages.

For example, the authblk package seems to be able to handle cases where "some of the authors belong to the same organization."

\ documentclass {jsarticle}
\uspackage {authblk}

% title
\title {test document}

% author's name
\author[1]{National Taro}
\author[2] {Private Ichiro}
\author[1] {National Jiro}

% affiliation
\affil[1]{A certain national university}
\affil[2]{A certain private university}

% Japanese language support
US>\renewcommand\Authsep
US>\renewcommand\Authand
US>\renewcommand\Authands

\begin { document }
\makeetitle
\end { document }

"However, the default setting is ""National Taro, Private Ichiro, and National Jiro"" and it does not match the Japanese documents, so

% Japanese support
US>\renewcommand\Authsep
US>\renewcommand\Authand
US>\renewcommand\Authands

The separator has been changed at . You may want to change it accordingly.

If you have two or more authors who belong to the same group, you can use \thanks after the second author and enter the footnote number directly with \footnotemark [number].