Can you share more insite on what your trying to attain, Are your looking just for a script if yes...

var groupMem = new GlideRecord('sys_user_grmember');
groupMem.addEncodedQuery('group='+ groupSys_id); // append group sys_id
groupMem.query();
while (groupMem.next()){
gs.print(groupMem.user.toString());
}

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