Flashing Buffer Region in other Window

[Nordlöw]

I am trying to find a function that temporarily highlight/flash the a
buffer region in a window other than the active one (other-window).
Neither hl-line-highlight nor highwin works. They require the flashing
window to be active. Do I have to create the overlay myself and delete
it after a timeout? How does grep and occur solve their flashing? Any
other package to recommend for this purpose?

Thanks,
Nordlöw