There has been too many. But Bollywood doesn't need billions of dollars worth technology to reunite families! We have (a)fate and (b)a song that the families sing and dance to in happy days(kids are young, they learn fast). Decades later, due to fate family gets placed into a 1 mile radius, and the kinship-proximity sensor gene trigger the release happiness hormones which in turn makes the family members break into song and dance.
Technology is catching up it seems ...