  Studying generalized non-local theories brings insight to the foundations of
quantum mechanics. Here we focus on non-locality swapping, the analogue of
quantum entanglement swapping. In order to implement such a protocol, one needs
a coupler that performs the equivalent of quantum joint measurements on
generalized `box-like' states. Establishing a connection to Bell inequalities,
we define consistent couplers for theories containing an arbitrary amount of
non-locality, which leads us to introduce the concepts of perfect and minimal
couplers. Remarkably, Tsirelson's bound for quantum non-locality naturally
appears in our study.
