A gateway relaying node for the authentication of a group comprising a plurality of wireless communication devices localized in the vicinity of said node and requesting access to a wireless communication network, the gateway relaying node being adapted to communicate directly with the requesting wireless communication devices and with the wireless communication network, the gateway relaying node being further adapted to: - receive (214, 215) all or part of a synthetic authentication vector generated by an authentication server, the synthetic authentication vector being derived from a set of individual authentication vectors, said set comprising one individual authentication vector per requesting wireless communication device belonging to the group, an individual authentication vector being determined using a random number RAND generated for registering the whole group of requesting wireless communication devices, the synthetic authentication vector being derived by sampling each individual authentication vector using a sampling function SFm and by concatenating the sampled version of said individual authentication vector, the sampling function SFm being selected depending on the value of the random number RAND, the random number RAND being also transmitted as a part of the synthetic authentication vector; - generate a local AUTHENTICATE command for each of the requesting wireless communication devices, a local AUTHENTICATE command being composed of the random number RAND and of the bits extracted from the synthetic authentication vector and corresponding to the sampled version of the individual authentication vectors corresponding to the requesting wireless communication devices for which the local AUTHENTICATE command is intended; - transmit the local AUTHENTICATE commands (217a, 217b, 217c) to each of the requesting wireless communication devices. - receive (214, 215) all or part of a synthetic authentication vector generated by an authentication server, the synthetic authentication vector being derived from a set of individual authentication vectors, said set comprising one individual authentication vector per requesting wireless communication device belonging to the group, an individual authentication vector being determined using a random number RAND generated for registering the whole group of requesting wireless communication devices, the synthetic authentication vector being derived by sampling each individual authentication vector using a sampling function SFm and by concatenating the sampled version of said individual authentication vector, the sampling function SFm being selected depending on the value of the random number RAND, the random number RAND being also transmitted as a part of the synthetic authentication vector; - generate a local AUTHENTICATE command for each of the requesting wireless communication devices, a local AUTHENTICATE command being composed of the random number RAND and of the bits extracted from the synthetic authentication vector and corresponding to the sampled version of the individual authentication vectors corresponding to the requesting wireless communication devices for which the local AUTHENTICATE command is intended; - transmit the local AUTHENTICATE commands (217a, 217b, 217c) to each of the requesting wireless communication devices.