Sounds like you want to model the effect of actually changing the surface a low-e coating is on, between surfaces two and three. Cool! Got VC? ;) You can certainly model it, we'll leave the question of whether it's physically possible over here, on the side for a sec. ;)
You could use the SwitchableGlazing object to model this, and then use the SimpleGlazingSystem for the window materials. Moving the low-e coating around will affect the u-value and SHGC together, so you could use Window or Optics to compute the Big Three (VLT, SHGC, U) for two different IGU configurations, make the two materials, make two constructions that use these materials, and apply them to a window subsurface with a shading control.
P.S. You don't even need to use Window or Optics, if you have a sense of what these parameters should be (perhaps you have mockups you've tested yourself, or have inferred the parameters) you can simply plug them into the SimpleGlazingSystem materials.
