对齐环境中的方程式网格，每个方程式都有自己的参考

Question

我想要实现类似下图所示的例子。

我已经有了一个解决方案；然而，它似乎需要创建很多minipages 和子方程环境，而且方程式不会出现。我希望等号全部对齐，并且每行中的垂直对齐（例如方程式 6a 与 6b/c）或水平对齐（例如 (6a)-(6c) 与 (7a)-(7c) 或 (8a)-(8c) 不对齐）没有差异。我希望网格中的每个方程式都有自己的标签和参考，这样我以后就可以引用它们，而不必为每一行制作一个通用标签并只能引用它。

\documentclass{article}
\usepackage[utf8]{inputenc}

\global\long\def\pd{\partial}%
\global\long\def\div{\boldsymbol{\nabla}\cdot}%
\global\long\def\grad{\boldsymbol{\nabla}}%
\global\long\def\curl{\boldsymbol{\nabla}\wedge}%
\global\long\def\lap{\nabla^{2}}%
\global\long\def\a{{\rm a}}%
\global\long\def\at#1#2{\left.#1\right|_{#2}}%
\global\long\def\ve#1{\bf #1}%
\global\long\def\jumppm#1{\mathbf{\left[#1\right]_{-}^{+}}}%

\usepackage{amsmath,amsfonts,amssymb}
\usepackage{graphicx}
\usepackage{cleveref}

\crefformat{equation}{(#2#1#3)}
\crefrangeformat{equation}{(#3#1#4)--(#5#2#6)}

\begin{document}

\begin{subequations}
\setlength{\tabcolsep}{0pt}
\noindent\begin{minipage}{0.3\hsize}
\begin{equation}
    \jumppm{\varepsilon\ve{E}\cdot\ve{n}} &= \xi, \notag
    \addtocounter{equation}{1}
    \label{eq:E.n-jump}
\end{equation}
\end{minipage}\begin{minipage}[b]{0.2\hsize}
\begin{equation}
    \jumppm{\ve{B}\cdot\ve{n}} &= 0, \notag
    \label{eq:B.n-jump}
    \addtocounter{equation}{1}
\end{equation}
\end{minipage}\begin{minipage}[b]{0.3\hsize}
\begin{equation} 
    \jumppm{\ve{J}\cdot\ve{n}} &= 0, \notag
    \label{eq:J.n-jump}
    \addtocounter{equation}{1}
\end{equation}
\end{minipage}
\hfill\cref{eq:E.n-jump,eq:B.n-jump,eq:J.n-jump}
\end{subequations}
\begin{subequations}
\setlength{\tabcolsep}{0pt}
\noindent\begin{minipage}{0.3\hsize}
\begin{equation}
    \jumppm{\ve{E}\cdot\ve{t}_1} &= 0, \notag
    \label{eq:E.t1-jump}
    \addtocounter{equation}{1}
\end{equation}
\end{minipage}\begin{minipage}[b]{0.2\hsize}
\begin{equation}
    \jumppm{\dfrac{1}{\mu}\ve{B}\cdot\ve{t}_1} &= 0, \notag
    \label{eq:B.t1-jump}
    \addtocounter{equation}{1}
\end{equation}
\end{minipage}\begin{minipage}[b]{0.4\hsize}
\begin{equation} 
    \jumppm{\dfrac{1}{\sigma}\ve{J}\cdot\ve{t}_1} &= \jumppm{(\ve{u}\cross \ve{B})\cdot\ve{t_1}}, \notag
    \label{eq:J.t1-jump}
\end{equation}
\end{minipage}
\cref{eq:E.t1-jump,eq:B.t1-jump,eq:J.t1-jump}
\end{subequations}
\begin{subequations}
\setlength{\tabcolsep}{0pt}
\noindent\begin{minipage}{0.3\hsize}
\begin{equation}
    \jumppm{\ve{E}\cdot\ve{t}_2} &= 0, \notag
    \label{eq:E.t2-jump}
    \addtocounter{equation}{1}
\end{equation}
\end{minipage}\begin{minipage}[b]{0.2\hsize}
\begin{equation}
    \jumppm{\dfrac{1}{\mu}\ve{B}\cdot\ve{t}_2} &= 0, \notag
    \label{eq:B.t2-jump}
    \addtocounter{equation}{1}
\end{equation}
\end{minipage}\begin{minipage}[b]{0.4\hsize}
\begin{equation} 
    \jumppm{\dfrac{1}{\sigma}\ve{J}\cdot\ve{t}_2} &= \jumppm{(\ve{u}\cross \ve{B})\cdot\ve{t_2}}, \notag
    \label{eq:J.t2-jump}
\end{equation}
\end{minipage}
\cref{eq:E.t2-jump,eq:B.t2-jump,eq:J.t2-jump}
\end{subequations}

\end{document}

肯定还有比这更优雅的方法吗？