On solution level: there is Solution Folder to organize projects to be different groups which is logically organized, not physically (on disk);The logical relationship between a solution and its components does not necessarily mirror the way the solution and its components are stored on disk.Visual Studio provides Solution Folders to organize related projects into groups and then perform actions on those groups of projects.
On project level: there is File Filter to organize files logically, but not physically(on disk).
Important Note: changing file name directly in VS solution explorer does changer the file's disk name!!!
Note: A project can be part of one or more solutions but solutions can't be included within other solutions.
How to create empty solution file?
File->new project ->visual studio solutions.
Miscellaneous Files and Folder
Those files don't belong to the solution, but they are used in developing the solution. Like directly open some files when opening a solution. If enabling to show the miscellaneous Files Folder, all used files or things can show up in your solution.
How to show the folder? Option->environment->document->show miscellaneous files folder.
To display the Miscellaneous Files Folder
1. On the Tools menu, select Options.
2. In the Options dialog box, expand the Environment node and choose Documents.
3. Select Show miscellaneous files in Solution Explorer.
4. Specify the number of documents you want to appear in the folder.
Projects manage links/files: http://msdn.microsoft.com/en-us/library/7kxx8f8e(VS.80).aspx
Application Solution Organization Three Ways
There are three main models to consider for partitioning solutions and projects. In order of preference, these are:
1. Single solution
2. Partitioned single solution
3. Multi-solution