I remember having discussions with the local public school where they suggested things like private school and homeschooling. It was sort of annoying, since they have a duty to teach my kid. But I think they were actually just trying to come up with what they thought were good options. We made it clear that we wanted to make it work with the public school, and they ended up being very flexible.
In your situation, there is an HG program at the school. At least some of the kids in that program are likely to younger siblings, yes? I would ask the school what they do with the siblings of kids in the HG program. Do they group them? (if not they should...) Do they differentiate? Is there any chance you can seek out a parent of a kid in your DD's class who has a sibling in the same situation? Obviously, each kid's needs are different, but grouping some kids who are likely to be closer in GT range than just random placement may be a good idea.
I think it's good to meet with the school and ask what they have to offer, then bring up some of your ideas. Good luck!
