Да, уже понял.
Решение:
var group, part1, part2, part3;
group = 'Group Status';
part1 = 'online';
part2 = 'away';
part3 = 'away';
if( part1 === 'offline' || part2 === 'offline' || part3 === 'offline' ){
group = 'Offline';
console.log('One of the users is offline. Group status: ' + group);
}else if( part1 === 'away' || part2 === 'away' || part3 === 'away' ){
group = 'Away';
console.log('One of the users is away. Group status: ' + group);
}else if( part1 === 'online' || part2 === 'online' || part3 === 'online' ){
group = 'Online';
console.log('All users are online. Group status: ' + group);
}else{
group = 'Not found';
console.log('Status not found. Group status: ' + group);
}