Well, you could do it like this:
Have three choices, and have the first three options be choices. Have the 4th option say 'More Options'. In the 'More Options' handler, do the same thing! Does that make sense?
i already taught about this myself, but than it would take ages to do it because of this:
when you whant to go to the next you have to insirt a new choices (only 3 left) but when you want to make it so he can go back too it whould take hell of a work (and only 2 choices left everytime)
besides that 2 reasons it looks very crappy to have only 2 choices at a time
this looks like a simple script, anyone who could do it (perhaps modern algebra?)