Accessing Peer DNS IP Address

Hello,

I would like to redirect all DNS request of one specific host in my network to the upstream PPPoE Peer DNS of my provider.
So in other words, I want to redirect the DNS requests of this specific host via DstNAT (all other hosts in the network shall be allowed to use whatever DNS server they want).

How can I specify the redirect destination when getting the Peer DNS IP address dynamically from my provider?
I highly assume that it cannot be done via the GUI. Is there a way to access the PPPoE Peer DNS IP address via a script?

Thanks a lot in advance,

Thomas