We investigate two closely spaced 2D electron systems in a quasi-Corbino geometry with independent contacts to both layers. Magneto-transport and drag experiments show that at the systems total filling factor 1 the drive current diminishes with increasing interlayer interaction (parameterized by the ratio of layer separation and magnetic length) while voltages of equal magnitude build up over both the drive and the drag layer. The identity of both voltages is resilient to thermal perturbations which contrasts markedly to the behavior observed in Hall bars.