[libvirt] question about connection between vms in two physical hosts

Hi there, I have some vms in two different physical hosts, the hosts are connected directly instead of a switcher, I'd like to make all these vms connected. the condition right now is that vm network type is nat, vm behind nat cannot get the new connection inbound, I suppose if I can make the inbound connection acceptable or if there is any other solution ? Thank you best wishes bill