Use two controllers for the same input

[Nostalgie in HD]

I want to play Wind Waker with a GC controller connected via the official Wii U adapter (native Dolphin driver method) and my keyboard/mouse at the same time.

How may I tell Dolphin to use both controllers for the same port?

[JosJuice]

This isn't possible if you're using Dolphin's native support for the adapter.

[Nostalgie in HD]

What would I have to do instead then? I obviously read about vJoy, but do I have to uninstall the native driver way then? Or is there a way to have both options installed at the same time?