A messaging server system receives a message creation input from a first client device that is associated with a first user registered with the messaging server system. The messaging server system determines, based on an entity graph representing connections between a plurality of users registered with the messaging server system, that the first user is within a threshold degree of connection with a second that initiated a group story in relation to a specified event. The messaging server system determines, based on location data received from the first client device, that the first client device was located within a geo-fence surrounding a geographic location of the specified event during a predetermined event window, the geo-fence and event window having been designated by the second user, and causes the first client device to present a user interface element, that enables the first user to submit content to the group story.