Surely the other devices you'd be tethering to the iPad (on which you've created a wi-fi hotspot from a wi-fi connection) also have wi-fi so why not just connect them directly to the wi-fi connection?
Poorly explained by the OP.
What I suspect the use case to be is where Wifi is a paid service such as at some hotels. You'd typically pay for each device you connected to wifi, so OP presumably wants to share that wifi connection with other devices.
Can it be done with an ipad? Not in the basic system setup, though perhaps there's an app that would do something like that. Never heard of it, and there's not exactly a lot of demand for such a thing...