Create forums and groups for specific people

Hello, good morning, I am developing an implementation to create a collaborative web and I need to know if you can create groups that only specified people have access to and create several of these groups for different activities. Within these groups I need people to share files, have access to closed forums for them and send messages to each other.

I would be grateful if you could indicate how to do it, if there is a manual or number if possible to implement these functionalities.

I appreciate your help in advance.