How do I remove myself from a group?
To leave a group, go to your memberships page and scroll down to the section labelled "Delete your membership in a group". Choose the group that you want to remove yourself from, and press the Delete membership. You will be removed from the group and unsubscribed from its private mailing lists. No email will be sent to the group administrators.
To rejoin the group later, you should to follow the normal procedure for joining a group.
Based on How do I remove myself from a group? by John Reekie