Hi Marcus,
The MvvmToolWindows QuickStart we have shows how you can add view models. One of those examples is an auto-hidden tool window that auto-hides to the left. You could add multiple of those if you wish instead of a single one. This kind of code in that example would make sure they start auto-hidden left and are all in the same container:
toolItems.Add(new ToolItem1ViewModel() { State = ToolItemState.AutoHide, DefaultDockSide = ToolItemDockSide.Left, WindowGroupName = "Left Auto-Hide" });
toolItems.Add(new ToolItem2ViewModel() { State = ToolItemState.AutoHide, DefaultDockSide = ToolItemDockSide.Left, WindowGroupName = "Left Auto-Hide" });
toolItems.Add(new ToolItem3ViewModel() { State = ToolItemState.AutoHide, DefaultDockSide = ToolItemDockSide.Left, WindowGroupName = "Left Auto-Hide" });