# Put small title under name in a signature

I want to put a descriptive name under the name in a signature:

I currently have:

\def\sig#1{\vbox{\hsize=5.5cm
\kern2cm\hrule\kern1ex
\hbox to \hsize{\strut\hfil #1 \hfil}}}

\newcommand\signatures[4]{%
\hbox to \hsize{\hfil #1, \today\hfil}
\hbox to \hsize{}}

\signatures{Institution}{Name 1}{Name 2}{}


which is :

But I want:

What should be added to the code to show that?

I call it using

\signatures{Institution}{Name 1}{Name 2}{}

-

You could use a \shortstack{}, which allows you to use line breaks:
\hbox to \hsize{\quad\sig{\shortstack{#2\\[0.5ex]Advisor A}}\hfil\hfil\sig{\shortstack{#3\\[0.5ex]Advisor B}}\quad}

You can adjust the spacing between Name and Advisor using the optional length argument of \\.