Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive a group-specific radio network temporary identifier (RNTI) associated with non-orthogonal multiple access (NOMA); receive an indication of whether the group-specific RNTI is associated with contention-based NOMA or contention-free NOMA; and selectively use a group-specific multiple access (MA) signature or a UE-specific MA signature for a NOMA transmission based at least in part on the indication. Numerous other aspects are provided.