Change path of where tikz externalization saves the pdf and eps

Question

I am using the TikZ externalization to speed up the compilation process and to have the eps files for the admission of the article which I'm writing.

So I have lines like

\begin{figure}
    \input{../path/filename.tex}
\end{figure}

, which I want to replace with

\begin{figure}
    \includegraphics{../path/filename.eps}
\end{figure}

when I submit my article. The problem is that the TikZ externalization changes both 'path' and 'filename', so that I would have to use

\begin{figure}
    \includegraphics{some_other_filename.eps}
\end{figure}

when I use

\usetikzlibrary{external}
\tikzset{external/system call={lualatex \tikzexternalcheckshellescape -halt-on-error -interaction=batchmode -jobname "\image" "\texsource";pdftops -eps "\image".pdf;}}
\tikzexternalize

in the preamble of the document. I do not know yet how to make a bash script to process this change, but it would already be easier if the original path and filename would be maintained.

UPDATE. I just found in the PGFplots manual that one can change the filename with the command

\begin{figure}
    \tikzsetnextfilename{path/nameyouchoose}
    \input{../path/filename.tex}
\end{figure}

However, it seems impossible to use a relative path, something like

\begin{figure}
    \tikzsetnextfilename{../path/nameyouchoose}
    \input{../path/filename.tex}
\end{figure}

How can I use a relative path?