Sounds right. Every single one of the Osmonds married Mormons. Not one married outside of their church. Although Maria has married three times (twice to the same man!) but they were all Mormons too!!!!! I think the parents ruled that group with an iron hand, after reading the book from Donny Osmond about his life Like the Carpenters, a lot of stuff was going on behind the constant smiles. I believe Richard married his cousin!!.
I've always found the Osmonds creepy - except for Donny who seems like a nice man - but a lot of them their jealously of Donny is obvious in interviews and it doesn't say much about them.