Most of the time when a new group is created, separate permissions for this group are wanted. If this is the case for you, please first create a new permission set on the <a href="{base_url}&section=content&act=group&code=permsplash">Manage Permissions</a> page. Once you have created a new permission set for this group, come back to this page and for the option <i>'Use which permission sets...'</i>, select the newly created permission set. Now when you go to edit your forum permissions, your new group/set will appear.