If you've sequestered your classes within different namespaces, you won't get any name collisions unless you've managed to do something wrong. The most common error is excessive or inappropriate use of the 'using' statement, which can strip off namespaces completely and undo the protection they offer. Please post the offending code and the error messages you're receiving.
Also, I agree with tbscope: it looks like you're trying to emulate Java, rather than use good coding practices. Excessive namespace depth is not necessary in C++ and only serves to make code harder to read. If you need to organize classes, do so with libraries. If you're getting name collisions within your own project, that's a design problem, not a namespace problem.
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