Coordination of message thread groupings across devices of a communication system

A system that can coordinate user interface formats having customized threads comprising messages from a common thread. Each client device can be managed by a data structure that defines thread containers, where individual thread containers define threads and topics for each thread. Each thread can also be associated with unique groups of messages. The data structure can cause each client computer to display different user interface formats, with each format showing different threads for each user. Users engaged in a chat on a parent thread can split the parent thread into multiple child threads, that can each be associated with unique topics. The system can then associate individual messages of the parent thread with each child thread. The system provides more granular control of user interface formats to allow users to separate messages of high-priority topics.