Tikz: Setting an anchor in a pic for relative positioning

Question

I have created a pic of a simple polygon which I want to use and reuse to create tikzpictures containing copies of it positioned relative to each other. How do I do that?

If I did not have the pic, I would use the positioning library and position relative to the polygon's corners. Can I do something similar here with a pic?

The expected result is something more elegant and reproducible than this. Thanks.

\documentclass[class=article,border=5pt,tikz]{standalone}
\usetikzlibrary{shapes.geometric}

\tikzset{fig/.pic={code={%
  \begin{scope}
   \node[regular polygon,regular polygon sides=6,draw,minimum width=3cm]
   (hexagon){};
   \foreach \x [evaluate=\x] in {1,...,6}
   {\node[draw,shape=circle,fill=white,opacity=1,minimum size=6mm] at (hexagon.corner \x){}; }
  \end{scope}
}}}%

\begin{document}
\begin{tikzpicture}[thick,x=1cm,y=1cm]
  \path (0,0) pic {fig};
  \path (2.265,1.305) pic {fig}; # inelegant + imprecise!
  \path (4.53,0) pic {fig};
  \path (2.265,-1.305) pic {fig};
\end{tikzpicture}
\end{document}

Answer 1

In this case, I would not use a pic but append after command. One benefit is that you can use the anchors of the node.

\documentclass[class=article,border=5pt,tikz]{standalone}
\usetikzlibrary{shapes.geometric}

\tikzset{myhex/.style={regular polygon,regular polygon sides=6,draw,
    outer sep=0pt,minimum width=3cm,
    append after command={[/utils/exec=\let\myln\tikzlastnode]
foreach \x  in {1,...,6} {(\myln.corner \x)
node[draw,shape=circle,fill=white,opacity=1,minimum size=6mm]{}}
}}}%

\begin{document}
\begin{tikzpicture}[thick,x=1cm,y=1cm]
  \path (0,0) node[myhex] (h1) {}
    node[myhex,anchor=corner 3]  (h2) at (h1.corner 1){}
    node[myhex,anchor=corner 3]  (h3) at (h1.corner 5){}
    node[myhex,anchor=corner 3]  (h4) at (h2.corner 5){};
\end{tikzpicture}
\end{document}