  We propose and study a conceptual one-dimensional model to explore how the
combined interplay between fixed resources and particle exchanges between
different parts of an extended system can affect the stationary densities in a
current carrying channel connecting different parts of the system. To this end,
we consider a model composed of a totally asymmetric simple exclusion process
(TASEP) connecting two particle reservoirs without any internal dynamics but
which can directly exchange particles between each other, ensuring nonvanishing
currents in the steady states. The total particle number in the system that
defines the "resources" available, although is kept constant by the model
dynamics, can take any value independent of the model parameters that define
the dynamics of the model. We show how the resulting phase diagrams of the
model are controlled by the parameters, which define the various dynamical
update rules together with the total available resources. These control
parameters can be tuned to make the density on the TASEP lane globally uniform
or piecewise continuous with localized domain walls, and can also control
populations of the two reservoirs. In general, the phase diagrams are quite
different from a TASEP with open boundaries. In the limit of large amount of
resources, the phase diagrams in the plane of the control parameters become
topologically identical to that for an open TASEP together with delocalization
of domain walls.
