Smart routing synchronization systems socialize a synthetic rebroadcast or group stream for enabling members of a user group to (re)broadcast select content to other members of the user group and collaboratively curate content delivery. The systems are based on a content-identification process and further a process for (re)broadcasting content. These processes are cooperable among a group of member clients each of which are in communication with at least two content sources. The synchronization process identifies select content and directs delivery of the content from an optimal resource for each member client via a smart routing protocol. The (re)broadcast process prompts delivery of the select content to members of the user group from a content origination member of the group, and group members are thereby able to simultaneously access the content for the purpose of providing a content-based platform for social interaction.