Pointing out the career development benefits of having extensive integration experience as part of the PMI communication process is one way. For the most competent among them, making them an integral part of the workstream, and/or having them serve as sub-team lead could make this benefit more tangible. And while not everyone will have incentive pay linked to synergy targets, celebrating the achievement of transaction business case milestones could include some treats or catered lunch during workstream meetings where the efforts of the team and notable contributions of individuals are noted and appreciated.
