On the face of it, it sounds like you need a Wall Scheule, and a claucluated Value parameter, and Conditional Formatting (to highlight) the results.
It may not be quite a simple as that- depending on your model: For example- say you have a really long, linear building which has a couple of walls that run the full lenght (creating a central corridor)- they will have cross walls hitting them, so breaking up their total length- but Revit will just tell you the total length of each Wall instance.
Hope that makes sense?