A good set up. This sentence doesn't make sense. I'm not sure if you trying to say this high school or all high schools. I had to read it twice and I still couldn't catch it.
"This will be a collaborative project between all athletes at the high school and will be a huge undertaking."
Maybe it's just all athlets at the school but I'm sure others may have sports equipment at home or whatever. By saying athlets it kind of excludes those who may have stuff and want to help but they themselves are not athlets.
Hope that makes sense.