[Tex/LaTex] Pgfplots for every group plot

Question

Similar to this question I want to align my y labels of groupplots.
The style

ylabel absolute, y label/.append style={yshift=0em},

does the trick, and thus I want to apply this to every group plot.
However, I don't really understand the settings category thing that's going on in tikz/pgfplots. I've tried many variations of the code below, which all compiled fine, but had no effect. Could someone point out how I can adress each group plot and append the above line to the style? *And maybe point out how to do this in general (where to find the subcategories etc)?

Basically, what I try to achieve is a way to modify the style of each group (groupplot?) and append the above ylabel absolute positioning. So something like every axis/ylabel, but for groups. (The former doesn't work, since it misplaces the ylabel of 3D plots.)

Minimal not-working example:

\documentclass{article}
\pgfplotsset{compat=newest}
\usepackage{pgfplots}
\usetikzlibrary{pgfplots.groupplots} % needs to be loaded exactly like this
\pgfplotsset{ /pgfplots/group/.append style = {
    ylabel absolute, y label/.append style={yshift=0em},
  }
}
\begin{document}
\begin{tikzpicture}
\begin{groupplot}[
    group style={
     group name=my plots,
        group size=1 by 2,
        xlabels at=edge bottom,
        ylabels at=edge left
    },height=4cm, width=4cm]
\nextgroupplot[ylabel={foo},]
\addplot coordinates {(0,0) (-0.1,-0.1) (-0.2,-0.2)};
\nextgroupplot[ylabel={bar},]
\addplot coordinates {(0,2) (1,1) (2,0)};
\end{groupplot}
\end{tikzpicture}
\end{document}

Answer 1

Looking at the code of the groupplots library, I see that the style /pgfplots/group/every plot is added to each \nextgroupplot. So to only affect axes in groupplots environments, append to that style, e.g.

\pgfplotsset{/pgfplots/group/every plot/.append style = {
    ylabel absolute, y label/.append style={yshift=0em},
  }
}

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\usepgfplotslibrary{groupplots} 
\pgfplotsset{/pgfplots/group/every plot/.append style = {
    ylabel absolute, y label/.append style={yshift=0em},
  }
}
\begin{document}
\begin{tikzpicture}
\begin{groupplot}[
    group style={
     group name=my plots,
        group size=1 by 2,
        xlabels at=edge bottom,
        ylabels at=edge left
    },height=4cm, width=4cm]
\nextgroupplot[ylabel={foo}]
\addplot coordinates {(0,0) (-0.1,-0.1) (-0.2,-0.2)};
\nextgroupplot[ylabel={bar}]
\addplot coordinates {(0,2) (1,1) (2,0)};
\end{groupplot}
\end{tikzpicture}

\begin{tikzpicture}
\begin{axis}[ylabel=abc]
\addplot3 coordinates {(0,0,0)(1,1,1)};
\end{axis}
\end{tikzpicture}
\end{document}