I watched this movie by chance on German TV supposedly sometime in the 2000s, missed the beginning and failed to note it's title. I searched IMDb for movies with the keyword 'commune' but did not find it. I liked it pretty much for it's authenticity. Maybe someone recognizes it and knows the title?
Time and place
From the way people were dressed and behaved I guess the movie is set in the 70s. I remember almost only scenes around the house so I don't know about shops or other public places.
The few cars I spotted and the way houses looked were a bit different from what I am used from US movie locations of that period so I think it might take place in Canada or Australia. Guessed from the optical appearance of the picture and the overall look the movie itself could have been shot in the 70s or 80s.
Basically the movie follows the everyday life of some 10-15 (?) people in their 20s (?) forming a hippie style commune. They live in a somewhat bigger house located (somewhat uphill?) in a kind of middle class housing area of what might be either a small town or suburb. At least partly they are musicians and other artists and the movie depicts lots of the typical discussions and quarrels (at times somewhat lengthy) between people being on a mission to find and explore themselves and how to relate with each other. I am quite sure drugs and lack of money were key points, too.
Subplot mentioned in this question's title
I don't remember any real plot except what happens towards the end of the movie: A teenage girl shows up and wants to stay at the commune. A little love story unfolds, conflicts arise. At some point her conservative parents show up to take her home. I am not sure whether she leaves with them or walks away on her own some time later on.