Conventional threshold models of price transmission allow for different speeds of adjustment to equilibria depending on the magnitude of price differentials between markets. However, these models typically assume only one underlying long-run equilibrium price relationship. In this article we develop a framework for allowing multiple equilibria and multiple speeds of adjustment with regime separation depending on the magnitude of trade flows between regions, rather than the magnitude of price differentials. Applying this framework to maize price transmission between South Africa and Zambia shows no transmission during periods of high imports, when the government was heavily involved in maize importation, but stronger transmission during periods of low imports when the government was not importing. Copyright 2012, Oxford University Press.