Hi Carla,
Yes, this is pretty easy to do and we do it all the time. We use regular buttons instead of radio buttions, but I guess you could do it with radio as well. Try these steps:
1. Create the set of radio buttons on the first view
2. Add rules to each of the radio buttons such that "If <RadioButtonNode> = View1" THEN "Switch views to View1" .... repeat for all four views.
3. Preview the form and make sure everything is working correctly. (Manually switch back to the view with the radio buttons for now).
4. Cleanup everything to look how you want it to.
5. Copy/paste the radio buttons to each of the four views.
6. From the Views task pane, double-click on each of the views and uncheck the box that says "Display view in view menu" - this is so users cannot circumvent your own view navigation system.
I hope that helps, good luck!
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge