I think there should a circuit for indoor brass. There was a group in North Carolina that became a member of the Atlantic Indoor Association. They were listed as an Independent World class in the program. I think their name was Platinum Indoor Ensemble. They were really good. It was their first year out. I saw them at Wakefield High Schools winterguard show. They had about 20 brass and percussion. They look to have been between the ages of 14 to 23. Their show was First Circle by Pat Metheny. The crowed really got into their show. There was a lot of talk about them after the show. Nothing but great things. I found their website and it looks good. You should and check them out at Platinum.Indoor.Googlepages.com
In other there should be a circuit for indoor brass and percussion, and WGI should add it.
Ted Hopkins