Computing systems, apparatuses, computer-implemented methods, and computer program products are disclosed for creating a shared communication channel in a group-based communication platform having a plurality of database shards. An example computer-implemented method includes generating a shared communication channel shard that is assigned a shared communication channel identification, a first set of shared communication channel attributes associated with a first group identification, and a second set of shared communication channel attributes associated with a second group identification. The method further includes generating first and second externally shared group-based shared communication channel interfaces based on the first and second sets of shared communication channel attributes, respectively. The method further includes transmitting the first and second externally shared group-based shared communication channel interfaces to a first client device associated with the first group identification and a second client device associated with the second group identification, respectively.