The following screen grab shows a single running Virtual Server host machine in the “Infrastructure Hosts” group. I've circled the state information which shows "responding", meaning that the server that's running Virtual Server 2005 R2 is available, this view is visible if you select the "hosts" view which I have also circled. You can see context sensitive actions in the 3rd pane (far right) which lists appropriate actions you can perform at this point.
You can see from the actions that you can "Create a new virtual machine" or "Add Host" for when you wish to add a new or existing Virtual Server into this group. For existing SCVMM managed Virtual Machines or guests you can just use "Move to Host Group" - which changes the parent host group association.
This next screen shows what view you see (and I've enlarged the screen area as well) when you select the "Virtual Machines" rather than the "Host" view. When in this mode in the bottom right corner in the Actions pane - you can see the Virtual Machine actions that you'd expect, such as Start, Stop, Pause, Save State, Shutdown and "Connect to Virtual Machine". There are a few new features as well, more about these I will post later when I've reviewed them, I do believe that the "migrate" option isn't available in this current beta version!