One of the neat features of Visual Studio Team System 2005 is the ability to set check-in policies at the team project level. You can, for example, require that each check-in be associated with a work item (for tracking requirements to code, or code fixes to bug reports), or require that the developer run static code analysis on the code before checking it in.
In a recent discussion, one of my colleagues asked if it was possible to configure check-in policies for individual projects within a team project. The answer, in terms of out-of-the box functionality, is no. But the good news is that it's possible to create your own custom check-in policy modules, and using this functionality, you could create a module that applies a given policy to a specified path within your project.
Some resources on this:
Overview of check-in policy
Jim Presto's blog, including info on creating custom check-in policies