Export your floor plan to dwg (whatever best represents the overall project, be it a slab edge plan, walls roof etc) Then import and link the dwg plan to your title block, reducing the size as req'd to get it to fit in your key plan area.
Now use filled regions in your titleblock to shade or otherwise identify the parts of the bldg. Create a yes/no parameter for each bldg area filled region you create. Associate each filled region's visible property with the matching yes/no parameter.
Now import the titleblock into your project and you can turn on/off the shading in the properties of the titleblock. Use Instance parameters in the titleblock family if you want to do this by sheet or type parameters if you want to have sheet types that are predefined for a bldg area (advantage if there are many and many views affected).
Your dwg is linked to the titleblock so it will update everytime you export the keyplan from Revit as long as you don't change the name or location. Now you just need to reload the titleblock into your project and you're back in business...