Different nameservers for different devices
I am running pfSense with BIND installed. On that machine, for a subnet of devices, I want the requests to go to OpenDNS and add my own records that would take precedence over OpenDNS. For the rest of the devices, I want to use Cloudflare's DNS (while keeping DHCP capabilities + own records). I do not have to use BIND, but it seems like Unbound does not support it.
Important: I will not set the DNS servers individually per device! It must be automatic based on the subnet the devices are in.
Alright. I solved this by using RZP. See my SuperUser question (https://superuser.com/a/1571028/739947) for more details.