Let $P$ be the set of people and $\mathcal{S}$ be the modified multi-set of subsets. By checking if an $\mathcal{S}$-saturated matching into $P$ exists (i.e. Hall's condition) you are indeed finding a diverse group.
If you are checking that some group $P$ is a putative solution first check if $|P| \neq |\mathcal{S}|$. If that holds then you can short circuit and say no. If $|P|=|\mathcal{S}|$ then solve for a perfect matching. If some member in $P$ or a subset in $\mathcal{S}$ is not matched then $P$the procedure is not a "diverse" groupthe exactly the same.
This can be done quickly via the Hopcraft-Karp algorithm (as you don't have weights over edges) or by implementing this as a Max-flow LP and using a solver. I'm willing to bet the solvers will work much faster in practice.