HI,

I created a script include:

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function getGroupMembers(grpName) {

      var mbrs = new Array();

      var grmember = new GlideRecord('sys_user_grmember');

      grmember.addQuery('group.name', grpName);

      grmember.query();

      while (grmember.next()) {

              mbrs.push(grmember.user.toString());

      }

      return mbrs;

}

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and then created a dynamic filter option.

javascript:getGroupMembers('IT Service Desk')