A database system usable in a high user concentration environment includes a central database containing content relating to associated users. The method and system allow a user to gain a better understanding of an existing underwater structure. The management frame, for example, may include a number of fields relating to a multicast transmission, such as one or more of a first field set to a value indicating a multicast transmission, a second field identifying a multicast address, a third field identifying a time for the multicast transmission, and a fourth field identifying a duration for the multicast transmission.