virtualbox.org

I have 1 physical server running ubuntu server 16.04 LTS. Installed is virtualbox v5.1.22. Installed additionally is phpvirtualbox (code modified for version check to match v5.1.22). The physical server has 4 onboard ethernet ports and one PCI ethernet card. The host server has all 5 ethernet ports plugged in with IPs assigned to each. In virtual box i have 6 virtual linux servers also running ubuntu server 16.04 LTS. Now right now each virtual server's network is set to bridge mode to the PCI network adapter. What i would like to do is create a virtual network whether its using Nat Network or NAT and "trunk" or "bind" that network to the 4 onboard ethernet adapters so that way i can assign the VMs to this network and they will have network connectivety through all 4 cables. VMware vSphere has a similar function like this however their platform is more iffy when it comes to creating my particular VMs..... Is what i am asking possible? If so...how is something like this done?

Do you have access to the network switch to configure the ports for link aggregation / LACP? This needs to be configured correctly on both ends of the cables.

Yes i have access to it all. This is in my home environment. The cable from the PCI adapter goes into an 8 port cisco switch which is where my PC and other devices plug into and that goes directly into port 2 of my router. The 4 onboard ethernet ports have cables running to a separate 5 part switch (same model as the 8 port) and that runs into port 4 of my router. FYI the router is a Linksys WRT 1200AC running DD-WRT.