Maybe you could try using groups:
For instance I use the group "all" with 1 question from group tema01c, 1 from tema01b, etc. for a total of 12 questions.

cleargroup{all}
\shufflegroup{tema01c}\copygroup[1]{tema01c}{all}
\shufflegroup{tema01b}\copygroup[1]{tema01b}{all}
\shufflegroup{tema01}\copygroup[5]{tema01}{all}
\shufflegroup{tema01a}\copygroup[1]{tema01a}{all}
\shufflegroup{tema02a}\copygroup[1]{tema02a}{all}
\shufflegroup{tema02b}\copygroup[1]{tema02b}{all}
\shufflegroup{tema02}\copygroup[2]{tema02}{all}
\insertgroup{all}

Best regards,
Rafael

The numbers after copygroup should be inside square brackets.

A command is already defined \exemplairepair

\element{Capitale}{
\exemplairepair 

\begin{question}{Paris}
What is the capital of France ?

\begin{reponses}
\bonne{Paris}
\mauvaise{Marseille}
\end{reponses}
\end{question}

\else

\begin{question}{Berlin}
What is the capital of Germany ?

\begin{reponses}
\bonne{Berlin}
\mauvaise{Bonn}
\end{reponses}
\end{question}

\fi
}

Amazing, thank you!

It's so nice to see that someone had the exact same goal as me and already created \exemplairepair. It's perfect.

I also need to toy a bit more with groups, seems like a powerful way to set up things. Combining \exemplairepair and \copygroup is probably the best way to keep things organized.

It also made me realize that the pdf documentation (https://download.auto-multiple-choice.net/automultiplechoice.pdf) is the comprehensive one. The html doc that is accessible through the gui doesn't seem to mention this command.

Btw I know it is nitpicking, but given the name I would have expected it to work as "\exemplairepair Even \else Odd \fi", and it's actually "\exemplairepair Odd \else Even \fi". I've also learned today that latex has an \ifodd does not an \ifeven command.

(Can't find how to delete a post; please ignore.)

To clarify I was wrong, exemplairepair does correctly select even, and not odd subjects.