Frameworks that incorporate communication into decentralized supervisory control theory address the following problem: find locations in the evolution of the plant behavior where supervisors send information so that a supervisor that was unable to make the correct control decision prior to receiving external information, is now capable of making the correct control decision. Existing solutions to this problem identify an earliest and a latest placement where the communication protocol leads to the synthesis of a correct control solution. In addition to the first and last communication opportunities, there may be a selection of intermediate possibilities where communication would also produce the correct control solution. We present a computable procedure to identify a broader range of suitable communication locations. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.