The Teleportation Hub is the series of teleports that connects you to the other Forbidden Islands from Goroma. It's necessary to do The Shattered Isles Quest to use those teleports. Once you have completed it, you'll have quick access to Ramoa, Talahu, and Malada following that order in the chain teleportation. The room located in each island contains two teleporters, the teleporters on the left take you to the previous island and the ones in the right take you to the next island in the chain. The hub in the third island (Talahu) has a Royal Mailbox under service for those who finished that other quest.
Note that due to being the first island in the sequence, Goroma only has the right teleporter, and while Malada is the last "reachable" island, it actually has an unreachable right teleporter, presumably with destiny to Kharos.