OpenVPN - Hypervisors and VMs communicating by VPN through the internet

I'm pretty lost with this problem (maybe I say something silly =D )...

I have two hypervisors (CentOS 7) connected by a VPN (OpenVNP).

In this scheme I have two virtual machines (VMA0 and VMB0) connected by a VPN (OpenVNP) ("tun").

What I need is "simple", but I have no idea how to do it: VMs in HOSTA and HOSTB communicate using the "10.0.2.0/24" and "10.0.4.0/24" networks.

Example: VMA1 (ip 10.0.2.11) succeeds in "pinging" VMB1 (ip 10.0.4.11) and that VMB1 (ip 10.0.4.11) succeeds in "pinging" VMA1 (ip 10.0.2.11).

In short, I need all VMs in the "10.0.2.0/24" and "10.0.4.0/24" networks communicate using the VPN.

To help (and I hope it helps =D ) I did a drawing with the scheme.

NOTE: Hypervisors should not run OpenVNP (server or client).

Thanks!