search all users without result limit and change a property of found users:
var myOrg = "230";
var group = people.getGroup("GROUP_Org_" + myOrg);
var scriptUsers = people.getMembers(group);
for each(var scriptUser in scriptUsers) {
if (scriptUser.properties.organizationId != myOrg) {
logger.log(scriptUser.properties.organizationId);
people.removeAuthority(group, scriptUser);
}
}