I have confirmed this feature with VirtualBox.
1. Configure two VMs, one is for Endian(VM1) and the other is for Ubuntu(VM2).
2. VM1 is equipped with three virtual ethernets (eth0, eth1, eth2) with the following mapping;
virtual ethernet Type of ethernet GREEN/RED
------------------- --------------------- --------------
eth0 GREEN Internal
eth1 RED Internal
eth2 GREEN bridged to NIC
3. VM2 has only one virtual ethernet with Internal.
This configuration allows a traffic to be carried in a scenario of;
(Untrusted network)---eth2---(Endian)---eth0---(Ubuntu)
Regards