Do check out the videos etc on our website explaining how key sharing works. Also, you can always use the free trial month to actually try out exactly how it works and how it matches your scenario.
AxCrypt as such does not store or share files, so the question about a folder is more up to how you make the folder available to several users. AxCrypt can keep all files in a folder encrypted easily enough, but it does not encrypt the actual folder. AxCrypt only encrypts files.