Allez cadeau. C'est un approche naïve et pas reentrant mais bon.

#include <iostream>

class Bidule
{
public:
Bidule() {};
virtual ~Bidule() {};

void bipbip() {
std::cout << "bipbip" << std::endl;
}

void coincoin() {
std::cout << "coincoin" << std::endl;
}
};

class Machin
{
public:
Machin() {};
virtual ~Machin() {};

void glouglou() {
std::cout << "glouglou" << std::endl;
}
};

class Truc : public Bidule, public Machin
{
public:
Truc() {};
virtual ~Truc() {};

void bipbip() {
this->Bidule::bipbip();
}

void glouglou() {
this->Machin::glouglou();
}
};

class GrosMachin : public Machin
{
public:
GrosMachin() {};
virtual ~GrosMachin() {};
static bool glou;

void glouglou() {
this->Machin::glouglou();
GrosMachin::glou = true;
}
};

class PetitBidule : public Bidule
{
public:
PetitBidule() {};
virtual ~PetitBidule() {};

void bipbip() {
if (GrosMachin::glou) {
std::cout << "glouglou" << std::endl;
} else {
this->Bidule::bipbip();
}
GrosMachin::glou = false;
}
};

bool GrosMachin::glou = false;