Using Segment Controller to "Push" rather than UINavigationController

Question

Hi, I;ve involved myself so much in NavigationControllers that I've become kinda ignorant with other options. Heres what i want to accomplish, I've built Subclassed ViewControllers to Push via NavigationController that works pretty fine.

However, to avoid the Idea of going back and getting to a new view doesnt fit for quick access since this is about calculator, i came up with using SegmentedControl.

I added UISegmentControl to the NavigationBar. What i want to accomplish, is on tapping of a segment, The Calculator1ViewController Loads below the NavigationBar. And on tapping another Segment, the previous ViewController is unloaded and a different "Calculator2ViewController" is loaded.

I'm not quite sure how to do it, loadFromNib may not work too well, cuz im using custom ViewControllers.

Any suggestions would be great help.