Can someone help me find a correct English word for this group activities?

Hi everyone!

I'm working on a new group chat app where people can gather and do a group activity for a planned period. For example, reading a half of a book weekly, running 3 miles daily, writing an article weekly, etc.

It essentially helps members do something in a regular basis to form a habit and grow together.

This might be called a group activity or a community activity. But I guess there should be better English word that means "an activity that is performed for a given period in a regular basis by a group of people to improve or grow themselves."

Can you come up with a better vocabulary than just group activity?