  Reliable quantum communication/processing links between modules are a
necessary building block for various quantum processing architectures. Here we
consider a spin chain system with alternating strength couplings and containing
three defects, that impose three domain walls between topologically distinct
regions of the chain. We show that -- in addition to its useful, high fidelity,
quantum state transfer properties -- an entangling protocol can be implemented
in this system, with optional localisation and storage of the entangled states.
We demonstrate both numerically and analytically that, given a suitable initial
product-state injection, the natural dynamics of the system produces a
maximally entangled state at a given time. We present detailed investigations
of the effects of fabrication errors, analyzing random static disorder both in
the diagonal and off-diagonal terms of the system Hamiltonian. Our results show
that the entangled state formation is very robust against perturbations of up
to $\sim10\%$ the weaker chain coupling, and also robust against timing
injection errors. We propose a further protocol which manipulates the chain in
order to localise and store each of the entangled qubits. The engineering of a
system with such characteristics would thus provide a useful device for quantum
information processing tasks involving the creation and storage of entangled
resources.
