turbo upgradebility?

[Isphius]

Isnt it possible(with some fab and trial and error and engineerin) to just run a smaller turbo and a larger turbo, and just use something like a wastegate or some other kind of valve to switch between them? or use a small turbo and once it exceeds its boost, to just use the wastegate to start spooling another turbo. Or even just put a small and large turbo on the same manifold with a cross over tube? I guess im basically trying to say...is there anyway to make your own sequential turbo system capable of higher horsepower. Just some questions i have no idea if this is possible or not...lol