STITCHING COMPLETED FILES

I have a subgrade plan with A LOT of existing contour lines.  The program cannot handle the entire plan so I uploaded the section plans (qt 4) and did my cut fill take off on each section.  Does anyone know if the completed projects can be stitched together?  I did it this way also, because when you bring the project into the into the line loading feature and when I attempt to use a filter to extract that particular line too many show up and I am unable to use that feature.  Along with the freezing, this has gotten old.  I can use the calculations of each individual section but I want to be sure it is producing the same numbers as if they were all in one file.  Hope that makes sense.