node host1, host2 {
    $type = cron1
    ...
}

node host3, host4 {
    $type = cron2
    ...
}


cron { 'cron-apt':
    command => $type ? {
        cron1   => 'command1',
        cron2   => 'command2',
        default => 'command3',
    },
    user => root,
    hour => 2,
    minute => 0
}