Complex sentence: Il Divo is related indirectly in terms of sponsorship and help with the French NGO SMTA Assistance Médicale Toit du Monde since 2005, of which Sébastien is the international official sponsor, and with Sanfilippo Children's Foundation in which Sébastien's global ambassador.
Split into simpler sentences: Il Divo is related indirectly in terms of sponsorship and help with the French NGO SMTA Assistance Médicale Toit du Monde since 2005, which Sébastien is international official sponsor. And with Sanfilippo Children's Foundation in which Sébastien's global ambassador.