I do a 3 gun competition which involves rifle, shotgun and pistol. It is scored individually by firearm and then an overall score. Is that the type of thing you are asking about? We typically use an AR-15, high cap pump shotgun and semi-auto pistol but the individual is free to use any configuration. There are different classifications based on equipment types. As far as efficiency at the shoot, we break up in squads and have officials in each squad. Your fellow squad members help with the scoring and patching/setting up the targets after each shooter.

A quick call to the NRA should tell you who in your area would be qualified to assist you.

Oh, those are FUN. I grew up in South Georgia doing that in the holiday season. All of ours were 15-20 meter stationary targets using 12g shotguns with #8 shot. Single ammo was the local standard, kept it easy, controlled ammo distro and loaded weapons, etc. and just about anybody could at least hit the pole from 15m with a 12g, so it was full of kids and women, too, which really improved the numbers and dollars. Rotation would start with minimum number of shooters. One shot each. Single pellet closest to the cross hairs won. Tremendous fun. 3 bucks per shot. Made a ton of money (at the one my father ran) for their local Shiners selling sodas and snacks. Sometimes had BBQ night, which always sold out. Had local companies doing sponsorships. Of course, those places are now full of homes and WalMarts, so we dont have them anymore, but they were a blast. Whatever you do will be fun, just keep the drunks out