Methods, systems, and devices for wireless communications are described in which multiuser superposition transmission (MUST) is used to provide multiple concurrent sidelink transmissions using a same set of time and frequency resources. A transmitting user equipment (UE) may provide an indication of concurrent MUST transmissions in sidelink control information (SCI), and a receiving UE may decode one or both of a MUST base layer communication and a MUST enhancement layer communication. The base layer communication may include broadcast or groupcast transmissions to multiple UEs, and the enhancement layer communication may include a unicast transmission between the transmitting UE and a single receiving UE. The indication of concurrent transmissions may be provided in a first stage SCI, and parameters for decoding the base layer and enhancement layer transmissions may be provided in one or multiple second stage SCI transmissions.