Lol, you're the boss of the ponies and you're the boss of the kids. They do what Ma tells them or else bad things happen. Does she have a cell phone she's fond of? A party she was wanting to go to? Or a car?
If she can't fall off the side of the bridge, you could always try blindfolding her and leading her over.
Or maybe even a fly mask might help.
If she doesn't like the noise, put some horsey earplugs (or a big wad of cotton or whatever) in and a fly bonnet over it and march her through.
You might try working with her. Grab a crop or dressage whip, and do some groundwork. She halts when you halt, walks when you walk, and turns when you turn, or else you tap her with the whip. Once you get her listening to you, go to the bridge. Confidently walk up to it. Do not get in front of her and attempt to drag her. Don't even look at her. Look at the bridge and calmly use the whip to ask her to move forward. If she refuses, spin her in a circle and present her again. Repeat however long as it takes for her to get a step closer. When she does, let her relax for a second. Work on baby steps. Don't try to wrestle with her. Let her choose for herself whether she wants to keep getting stung and spun or if it's better to just walk on the stupid bridge. Even if you don't get across but get closer than normal, that's good. Stop on a good note and don't be afraid to wait it out to get the progress you need.