Global functions vs. object orientation

Hallo all together,

In our C++/MFC project we have the following structure:

class A {
public:
	bool FileExists(...);
};

class B {
public:
	bool FileExists(...);
};

class C {
public:
	bool FileExists(...);
};

//...

In some classes there is the same function which checks the existence of a XML file.

But the classes are too different to create a base class to store the function.

So we decided to write "FileExists" as a global function and put it into
stdafx.cpp which is now our global function storage.

My question:

The advantage of an "old" language like C++ allows the usage of
global functions and variables, with leads to its disadvantage that object orientation
is broken.

What other stategies are available to solve the upper "problem" ?

And how can it be solved in languages like C# or Java in which global stuff is forbidden ?

Best regards

Tags: C++, C#, OOP