Yeah, I've had situations like that. I had a mum with her daughter and son on a tour a few years ago, and I charmed them all, and then asked the mum if she could lend me her daughter so I could take her out for a drink. She let me and I fucked her daughter.
But outside of the tour context I would advise you to approach the set, and talk to the family, and tell them (i.e., mum and grannie, "you must be proud of having such a lovely daughter/granddaughter") and then charm them and ask them if they can "lend" her to you for a minute for you to talk to her.
When I was around 20 or perhaps even younger, I once approached a girl at the museum, and it turned out she was with her mother and younger brother. I then went to the beach and we went on a date lol, but she was at the beach with her mum and sibling. Unfortunately, nothing transpired.
I met this local PUA here once who would sometimes approach a hottie he would see on the street (day game), and she would be with her dad and fam, and he would still take her out and smash. It also depends on the family dynamic, i.e., whether the dad has that "patriarchal" authority Teevs was talking about in the body count thread or not.
Just the other day, I grabbed this hottie's digits on a private tour with her dad and mum and sisters trailing behind.