  Electrical control of spin transport is promising for achieving new device
functionalities. Here we calculate the propagation of spin currents in a
graphene-based spin-current demultiplexer under the effect of drift currents.
We show that, using spin- and charge-transport parameters already obtained in
experiments, the spin currents can be guided in a controlled way. In
particular, spin-current selectivities up to 102 can be achieved for
measurements over a distance of 10{\mu}m under a moderate drift current density
of 20{\mu}A/{\mu}m, meaning that the spin current in the arm that is off is
only 1% of the current in the arm that is on. To illustrate the versatility of
this approach, we show similar efficiencies in a device with four outputs and
the possibility of multiplexer operation using spin drift. Finally, we explain
how the effect can be optimized in graphene and two-dimensional semiconductors.
