Can I instruct my pihole device to tunnel through my VPN

Expected Behaviour:

I've got a merlin firmware router. it can be, and has been, configured w/ a VPN subscription. The VPN provider's DNS servers had been hardcoded into merlin, but since using Pihole, the DNS entries in the merlin have been cleared and in place is the IP of the Pihole. The router handles DHCP responsibilities.

Anyway, the merlin router has the ability for static routes for the VPN tunnel... nothing fancy.
"Rules for routing client traffic through the tunnel"

My question is as i'm not familiar w/ this conceptually....
should i add an entry here for my pihole as well?

Actual Behaviour: