Now, that said, in an environment of like-ability students, I can see there being tremendous value in plenary sessions where students present their research to others, including at the elementary level. I don't think there is enough meat to elementary subjects the way they are usually taught for group discovery to be a meaningful learning method for young gifted learners.
This is how it works with my ds.
There are 5 of them in the same grade and in the same class. They have a morning math class where they work as a group all the time. They may take an old AMC8 test or Mathcounts test and then bounce solutions off each other when they are done.
There is a math contest this weekend and they are all attending. After they complete the test they will get together in a group and go over the whole test with no prompting. We will probably have to pry them away. It works very well.
ETA: When my ds went to the local public school his teachers would use him sometimes as a tutor/mentor to some of the kids until he put a stop to it.
