My gt.grandmother and her 2 siblings were living with their mother in 1841 along with an elderly couple. By 1851 the mother had disappeared and it looks like this couple are looking after them. In 1861 my gt. grandmother was 20 and described as daughter of this elderly couple. They must have been good people as three generations all kept the surname as their middle name. How do I add them as foster parents or adopters when they had known parents?