Autocomplete for multiple databases

Hello, our application uses multiple MariaDB databases (one for each customer, which are identical, and other "higher-level" databases to hold aggregated data, store customer invoice information, etc). I would like to have code completion for all these databases at the same time, is that possible?

Let's say our customers' databases are called `a`, `b`, `c` and so on, and our internal databases are called `internal_a`, `internal_b`, `internal_c`, and so on.

It would be nice if the autocomplete worked for both `a` (default schema/database, autocomplete works here) as well as all the internal databases at the same time. I can mark all these databases manually in the schema list in the connection's properties without problems, but the autocomplete only works for the default database, and PhpStorm's static analysis complaints about being "unable to resolve table" for any queries done to the internal databases (which I luckily can ignore because everything works).

Is there some way I can achieve what I want?