action group
noun[C]
ukusagroupofpeoplethatworktogether totrytoachievechangesrelatingto aparticularsituationor inordertohelpaparticulargroupofpeople:
form/join/set up an action groupShareholders in Mistral haveformedanactiongroupafter thecompanywasplacedintoadministration.
a policyholder/shareholder/investoractiongroup