How to create a group of minipages that can be spanned across columns but can't be broken in two pages?

Question

I'm trying to diagram an exam for an educational purpose. I'm using the package multicols to display questions in two columns. Each question of this exam is divided in three blocks:

1. base text
2. wording
3. answers

I've grouped each of these blocks, separately, in a minipage, so they can be unbreakable. We want these blocks to be able to span columns on the same page but we're struggling to discover how to prevent one question being divided in two pages.

Here is an example:

\documentclass[a4paper]{article}

\usepackage[utf8]{inputenc}
\usepackage[left=15mm,right=15mm,top=15mm,bottom=15mm]{geometry}
\usepackage[portuguese]{babel}
\usepackage{multicol}
\usepackage{blindtext}

\begin{document}

\begin{multicols*}{2}

\begin{minipage}{0.48\textwidth}
\noindent{\bf QUESTION 1}\\
\textbf{BASE-TEXT}\\
\blindtext
\end{minipage}
\vfill
\begin{minipage}{0.48\textwidth}
\textbf{WORDING}\\
\blindtext
\end{minipage}
\vfill
\begin{minipage}{0.48\textwidth}
\textbf{ANSWERS}\\
\blinditemize
\end{minipage}

\vfill

\begin{minipage}{0.48\textwidth}
\noindent{\bf QUESTION 2}\\
\textbf{BASE-TEXT}\\
\blindtext
\end{minipage}
\vfill
\begin{minipage}{0.48\textwidth}
\textbf{WORDING}\\
\blindtext
\end{minipage}
\vfill
\begin{minipage}{0.48\textwidth}
\textbf{ANSWERS}\\
\blinditemize
\end{minipage}

\vfill

\begin{minipage}{0.48\textwidth}
\noindent{\bf QUESTION 3}\\
\textbf{BASE-TEXT}\\
\blindtext
\end{minipage}
\vfill
\begin{minipage}{0.48\textwidth}
\textbf{WORDING}\\
\blindtext
\end{minipage}
\vfill
\begin{minipage}{0.48\textwidth}
\textbf{ANSWERS}\\
\blinditemize
\end{minipage}

\end{multicols*}
\end{document}

If you compile this code, you will note that the blocks of question 2 are spanned in the two columns, which is desirable (column constraint), but question 3 was broken in two pages (page constraint), which we cannot let happen.

We tried to use \samepage, which has no effect.

We tried also to add a \nobreak after first and second block. We haven't added a \nobreak after the third block since we do not want to inhibit a break at this point. This attempt holds page constraint, but broke column constraint, once every question was placed entirely in a column.

Is there a way to hold these two constraints at the same time in LaTeX?

Very best regards.

Answer 1

It's probably easier to use standard twocolumn for this rather than multicol as the global balancing makes it harder to know which column you are in.

\documentclass[a4paper,twocolumn]{article}

\usepackage[utf8]{inputenc}
\usepackage[left=15mm,right=15mm,top=15mm,bottom=15mm]{geometry}
\usepackage[portuguese]{babel}
\raggedbottom

\usepackage{blindtext}
\setlength\parindent{0pt}

\makeatletter

\def\hmm{\par\if@firstcolumn\else \par \nopagebreak \fi\par\bigskip}

\makeatother

\begin{document}



\begin{minipage}{\columnwidth}
\textbf{QUESTION 1}\\
\textbf{BASE-TEXT}\\
\blindtext
\end{minipage}
\hmm
\begin{minipage}{\columnwidth}
\textbf{WORDING}\\
\blindtext
\end{minipage}
\hmm
\begin{minipage}{\columnwidth}
\textbf{ANSWERS}\\
\blinditemize
\end{minipage}

\vfill

\begin{minipage}{\columnwidth}
\textbf{QUESTION 2}\\
\textbf{BASE-TEXT}\\
\blindtext
\end{minipage}
\hmm
\begin{minipage}{\columnwidth}
\textbf{WORDING}\\
\blindtext
\end{minipage}
\hmm
\begin{minipage}{\columnwidth}
\textbf{ANSWERS}\\
\blinditemize
\end{minipage}

\vfill

\begin{minipage}{\columnwidth}
\textbf{QUESTION 3}\\
\textbf{BASE-TEXT}\\
\blindtext
\end{minipage}
\hmm
\begin{minipage}{\columnwidth}
\textbf{WORDING}\\
\blindtext
\end{minipage}
\hmm
\begin{minipage}{\columnwidth}
\textbf{ANSWERS}\\
\blinditemize
\end{minipage}


\end{document}