Hi. I'm looking for a tool to run a small community. I'm hoping this crowd has seen something similar and can make recommendations. Here is the use case.

I'm part of a group of less than 50 people that teach an activity. I need to coordinate instructors support staff and location availability. As well as communicate and store files for instruction

• Id like a shared calendar that everyone can see and manage events. Each entry needs to have a spot to say where the event is taking place as well as time, date and a notes field to put student names.
• Id like a chat feature where requests to the group can be seen and responded to. (Hey, can anyone teach a class on this day?)
• id like a place to store documents and training materials. Ppts, maps and class standards

Thats kinda it. We are currently using an app called "Band" which is ok but I wanted to know if anyone else knew of something open source that doesn't rely on Google or fb.Thanks!