It is possible to set one or more parents for a device. The aim for that is, if all parent devices are down, alert contacts will not receive redundant alerts for dependent devices. This is very useful when you have an outage, say in a branch office, where normally you'd receive hundreds of alerts, but when this is properly configured, you'd only receive an alert for the parent hosts.
There are three ways to configure this feature. First one is from general settings of a device. The other two can be done in the 'Device Dependencies' item under 'Devices' menu. In this page, you can see all devices and with its parents. Clicking on the 'bin' icon will clear the dependency setting. Clicking on the 'pen' icon will let you edit or change the current setting for chosen device. There's also a 'Manage Device Dependencies' button on the top. This will let you set parents for multiple devices at once.
For an intro on getting started with Device Dependencies, take a look at our Youtube video