I tried finding something on internet, but it seems that all CMS's that support file sharing are with a lot of additional functions that I don't need this time.

I'm looking for a system that would provide dropbox functionality - file exchange between people (No need for pc sync) for a small group of individuals.

There are some project tracking cms that can do this, but as I mentioned earlier they have a lot of function I wouldn't be needing.

I'm thinking about, maybe using Joomla with some file management extension, but I think it could end up being way more complex than it needs to be.