Outputting notifications using device groups

A system that determines that devices are co-located in an acoustic region and selects a single device to which to send incoming notifications for the acoustic region. The system may group devices into separate acoustic regions based on selection data that selects between similar audio data received from multiple devices. The system may select the best device for each acoustic region based on a frequency that the device was selected previously, input/output capabilities of the device, a proximity to a user, or the like. The system may send a notification to a single device in each of the acoustic regions so that a user receives a single notification instead of multiple unsynchronized notifications. The system may also determine that acoustic regions are associated with different locations and select acoustic regions to which to send a notification based on location.