【Example 3】To distribute 11 papers to 4 experts for review, one expert should review 4 papers, one should review 3 papers, and the other two should each review 2 papers. How many different ways are there to distribute the papers?
Here, we first provide a solution based on the multi-group combination pattern.
It should be noted that in addition to combining the papers into multiple groups, dividing them into four groups with 4, 3, 2, and 2 papers respectively; the experts should also be combined into multiple groups, dividing them into three groups with 1, 1, and 2 people respectively, to undertake the review tasks for 4, 3, and 2 papers respectively. Therefore, this is a double multi-group combination problem, and by the multiplication principle, there are
$$
\begin{array}{l}
=831600 \\
\end{array}
$$

different ways to distribute the papers.