Automatic File Split Tool - Break Large Files into Smaller Ones - Re-Assemble Again

I need a program that can split a large file into smaller ones and then re-assemble it later. The program should be able to specify directories within the drives. The program should scan the directories at specified times and break up the large files into smaller ones (.001, .002, etc). The program should then be able to (upon request) re-assemble the smaller files back into the single (large file). I have used 7zip in the past to perform this task, however I need this to be automated. The system should have the following options: 1. Selection of Dir(s) within all visible drives 2. Threshold for file split (for example, 1GB, 400MB, etc) 3. File split size (for example, X number of 25MB files or X number of 3.98GB files) 4. Time(s) at which the program will run to scan and split 5. The ability to select a 'set' of files and re-join them. Must be able to run on Win7 x64 Suggest .NET (C#) but open to other suggestions. Please ask any questions.