The fifth generation of mobile cellular networks (5G) is designed to support a set of new requirements and use cases, including connectivity for the IoT (Internet of Things). Due to the industry and the user's expectation of having connectivity embedded into IoT devices, the “wholesale wireless connectivity” concept is gaining more and more attention. According to this concept, connectivity providers sell connectivity to 3 rd parties, which in turn provide it to their own devices. However, this concept brings also new architecture and security requirements that are not fully addressed by the state of the art. Taking advantage of the flexibility provided by virtualization technologies (including network slicing), we propose in this paper a new 5G-SSAAC (5G Slice Specific Authentication and Access Control) mechanism that delegates authentication and access control of the devices to the 3 rd parties providing these devices, thereby decreasing the load of the connectivity provider's CN (core network), while increasing flexibility and modularity of the whole 5G network.