Is it possible to have multi-key discriminators?

[GCastilho]

Do you want to request a feature or report a bug?

Feature

What is the current behavior?

Currently, we can only have one key as the discriminator key, but as discussed in #5846 (I think it was closed by accident) it seems like a nice feature

What is the expected behavior?

The possibility to use multiple keys as discriminators to track "sub-versions" of a discriminator. It's kind of related to #2851 since it would allow the use of multiples discriminators on the same document

Are there any plans for implementing this in the future?