If you think about it, what you're saying doesn't make physical sense, whether we're talking about the real world or the programming world.
How can you have an apple inside of an orange, but then have that orange also inside the same apple?
To avoid circular #including, use a forward declaration of the class you wish to use. If you showed a concrete example, one of us could probably show you how to re-organize the code.
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/// Fob.h: ///////////////
class Foobar; // forward declaration
class Fob {
Foobar* foobar;
};
/// Foobar.h: ////////////
#include "Fob.h"
class Foobar {
};