One of the purposes of rebirth is to experience the infinite on a finite basis. This is generally done by changing the outer circumstances of life. It means being born in different climes and circumstances of life.
Whether the same people will be born together or not depends upon whether they have the same aspiration and the travelers on the same path to the same goal. This is not very common and hence it has been rightly said that ‘children of the same family are rarely born under the same roof.’ In other words we have a physical family which is the family of our birth and it ceases with death of the body. Then there is a family formed by common interests and common thoughts. These may extend beyond one life.
But there is a spiritual family where the bonding and togetherness is due to the common spiritual aspiration. This is the true family and those who come together in this common aspiration generally come or meet together again and again in different lives.
About Savitri | B1C2-10 Condition of the World (p.18)