Allow External and Internal materialization of multi-source to fail/update individually

Hi, all.
First of all thanks in advance for your attention, and efforts on such a great product.
Since I haven't found any docs or examples regarding my current usage (please if this already exists or there's a better way of doing this, disregard this request and advice) here goes my suggestion:
It would be nice to have a way to gracefully update/fail per source, if a view that has Materialization enabled and target a multi-source source model, because things can get, messy if I have to create a view per source and Materialize each one and only then create a unified (UNION) view.
Using this approach also obligates me to implement custom insert/update/delete/based on the discriminator column.

Thanks again.