Keys: Is This Way of Encryption Already Invented?
Maybe not the precise scheme, but having elements in the key select a particular cipher is pretty common - mainly by persons starting crypto. All in all they are generally not secure and end up discussing Kerckhoffs's principle.

It is not easy to create a modern, secure cipher by alternating between a lot of insecure classical ciphers. No doubt it can be done, but this scheme is not intricate enough for that; it will fail basic randomness tests and will probably fall to frequency analysis as well.