pgfkeys: firing .unknown handler for a "parent" key

Question

Using pgfkeys, I automatically build some subkeys when an unknown key is encountered. See MWE below.

I would like to avoid having to set the test key (which is what fires the .unknown handler) before accessing the subkeys, ie. make it implicit. Is this possible?

\documentclass{article}

\usepackage{pgfkeys}
\usepackage{etoolbox}

\newcommand\buildkeys[1]{%
    \pgfkeys{%
        /mypath/#1/a/.initial=N/A,
        /mypath/#1/b/.initial=N/A,
    }
}

\pgfkeys{%
    /mypath/.unknown/.code={%
        \expandafter\buildkeys\expandafter{\pgfkeyscurrentname}%
    }
}

\pgfkeys{%
    /mypath/.cd,
    test, % Needed to fire the .unknown handler. I would like to avoid this
    test/a=test a,
    test/b=test b,
}

\begin{document}

should be "test a": \pgfkeysvalueof{/mypath/test/a}

should be "test b": \pgfkeysvalueof{/mypath/test/b}

\end{document}

Answer 1

Per @HenriMenke that is not possible, so I may instead use this solution (but I'm still open to better ways!)

\documentclass{article}

\usepackage{pgfkeys}

\newcommand\mykeys[2]{%
    \pgfkeys{%
        /mypath/#1/.cd,
        a/.initial=N/A,
        b/.initial=N/A,
        #2,
    }%
}

\mykeys{test}{%
    a=test a,
    b=test b,
}

\begin{document}

should be "test a": \pgfkeysvalueof{/mypath/test/a}

should be "test b": \pgfkeysvalueof{/mypath/test/b}

\end{document}