libvirt users - Feb 2017 - Communicating between libvirt contains on separate hosts

I have a group of CentOS 7.2 servers running as VMs under VMware's ESXi 
6.0. These all reside on the same subnet and we have no problem 
communicating between the different virtual servers. In addition, each 
of these servers run a number of libvirt-based LXC containers, also 
based on CentOS 7.2. The hosts can communicate with their containers 
without issues and the containers on a given server can communicate with 
each other. However, containers hosted on two different servers cannot 
communicate with each other or with other servers.

If we duplicate this setup using KVM based VMs instead of ESXi VMs 
everything works fine--there is no problem communicating between LXC 
containers regardless of which VM hosts them.

I assume this is not a libvirt issue but if anyone has encountered this 
issue in running libvirt containers under a VMware environment and has 
found a solution, I'd appreciate hearing from you.

Thanks very much,

Peter