Stop notification toasts but keep the sound

The title says it. Is there any way to do this?

We need the sounds to warn staff that documents and photos are arriving in Dropbox, but the notifications toast pops up right over top of a key app process button which cannot be moved. I did have a registry hack that put the toasts at the top right of the screen, but that no longer works (a Windows update broke that workaround)

This is normally not a problem; you just click the arrow to make it go away, but sometimes, literally hundreds of documents and photos all arrive together over periods of up to fifteen minutes... and you can't clear the toasts quick enough to do any work

What is a notification toast?
Is it this ?

Hah, that is funny.

No, it the little dialog box that pops out of the bottom right side of the screen when you receive a notification, like this....