The CoViewer let you become the sharing center in a group.
The CoViewer App is a wireless many-to-many photo sharing utility. When people get together in family, party, classroom or conference, the CoViewer users can present photos directly onto the screen of AppleTV, PC, projector, mobiles and tablets of the audience. As the presentation is carrying on, the informative slide can also be downloaded by audience.
The CoViewer App also fits the scenario where a group want to be freely sharing and browsing, transferring photos of each others. The CoViewer could setup a mobile web app for your photos to allow every group members to randomly browse the photos on their own devices. At the same time, you might be browsing other CoViewers.