家谱树：如何以父母为中心？

Question

在这种情况下，如何使节点“Istri”、“Anak-1”、“Anak-2”和“Anak-3”居中？

\documentclass{article}
\usepackage[all]{genealogytree}
\usepackage{incgraph}
\usepackage{tikz}
\gtrset{highlight/.style={pivot,box={colback=yellow!20,no shadow,fuzzy halo}}}
\usepackage[rm,medium]{roboto}

\begin{document}

\begin{inctext}[border=5mm]
\begin{tikzpicture}
\genealogytree[template=signpost,
    level size=2cm,
    box={bean arc,sharp corners=north,bottom=5mm},
    tcbset={
    male/.style={
        colframe=blue!50!black,
        interior style={top color=blue!20,bottom color=blue!50!yellow!5},
        drop fuzzy shadow=blue!25!black!30},
        female/.style={
        colframe=red!50!black,
        colback=red!50!yellow!5,
        interior style={top color=red!20,bottom color=red!50!yellow!5},
        drop fuzzy shadow=red!25!black!30}
      },
      ]
      {%awal
parent{
g[highlight,female]{Anak-1}
g[highlight,male]{Anak-2}
g[highlight,female]{Anak-3}
    
parent{
        g[highlight,male]{Aku}
        parent{
        g[male]{Ayah}
        p[male]{Kakek}
        p[female]{Nenek}
} 
        parent{
        g[female]{Ibu}
        p[male]{Kakek}
        p[female]{Nenek}
}} 
%---------------------------------------
parent{
        g[highlight,female]{Istri}
        parent{
        g[highlight,male]{Ayah Mertua}
        p[male]{Kakek}
        p[female]{Nenek}
        
}
        parent{
        g[highlight,female]{Ibu Mertua}
        p[male]{Kakek}
        p[female]{Nenek}
        
}}
}}%akhir
\end{tikzpicture}
\end{inctext}
\end{document}