A dynamic service group discovery and mapping approach avoids manual assignment of stream channels for transporting video services to the client devices that provide the video services to an end user. Client devices, such as set-top boxes, receive video services such as video on demand (VOD), switched digital video (SDV), pay-per view (PPV) and other narrowcast types of video for selective transmission. Each client device scans for visible stream channels, and sends a report indicative of visible stream channels to a dynamic mapping server. The dynamic mapping server applies aggregation rules for determining, based on the reported stream channels, which client devices are in the same service group. By receiving reports from each client device, the dynamic mapping server identifies groupings of service groups by combining sets of client devices receiving common channels, and “builds” the service groups as additional reports indicate common stream channels visible to multiple set top boxes.