Bridged networking and wireless packet capture

[arty]

I'm having a somewhat odd problem with bridged networking. I'm trying to create a lab where two vms are running centos 7 on my Ubuntu laptop, will communicate with each other over the wireless adapter, and another laptop will sniff the traffic with wireshark. The issue is that in wireshark I can see traffic to the router or external ips but nothing from vm to vm or vm to host.

Both VMs are using bridged adapters and my understanding was that all guest traffic is sent from the host's NIC to the router with the guest's IP and the host's MAC (meaning I should be able to see it in wireshark). What it looks like is happening is that Virtualbox sends directly to the other guest within the host. I'm not sure how to go about seeing where exactly the packets get diverted as they don't show up in wireshark on the host laptop either. I would very much like a better understanding of this if someone can point me in the right direction. Do bridged adapters communicate directly when connected to a wireless NIC? If so, is there a way force them to communicate through the router?

[socratis]

I'm not too strong in the networking, but the way that I understand it is the following:

[list]  WiFi
    |
  VBOX 
  /   \
VM1   VM2[/list]

Do you see any reason why VirtualBox should forward something to the WiFi and not use its knowledge of its own connections?