Communications among multiple nodes via a shared power line medium are carried out by dividing the available frequency spectrum in the shared power line medium into plural non-overlapping channels. A first channel is assigned to a first group of nodes, and a second channel, different from the first channel, is assigned to a second group of nodes. Communications between the first group of nodes can occur simultaneously with communications between the second group of nodes via the shared power line medium. Time slots may be assigned for the communications between the first group of nodes that occurs simultaneously with the communications between the second group of nodes via the shared power line medium. The simultaneous communications between different groups of nodes via a shared power line medium may be implemented using a frequency-hopping spread spectrum technique.