Icinga2 how to ping from one Host (Icinga) to other branch router (pfSense) machine to monitor a vpn tunnel

I learning about icinga2. I have one Icinga2 core as Master. Icinga-Host has been configured as Icinga-Sattelite. I am now facing a challenge in which I would like to monitoring one simple vpn tunnel between one icinga Host and its conected other branch network router (pfSense) over VPN.

ICINGA_SERVER —> Host (internal IP) ----> Branch Router (internal IP)

I can ping from Icinga-Host to its VPN-connected other branch router manually using CLI. How i can configure a ping from Icinga-Host to to its branch router (internal IP) using icinga2.

Thanks in advanced!.