You may disable email notifications of community updates by updating your profile settings:
- Select My Profile from your account menu (you must be logged in to view this)
- Your profile will be displayed. Click on the drop-down menu (your profile image) select 'Preferences > Manage Alerts'
- Under System select the feature that you wish to edit e.g. Groups
- Under Email, change the required setting e.g. "New group announcement", "New discussion announcement", "Replies in discussion"
If you no longer wish to participate in a group you can leave it and then request to rejoin at a later date if desired.