Adding "submenu" item to DataPortal context menu?

I’d like to add some items to the DataPortal context menu (via "Portal.Events.OnShowingContextMenu"), and want to know if I can add a “submenu” item (like the “New” popout item in the DataPortal context menu shown in the attached image).  I was hoping if I assigned a MenuPoint ID with a decimal value it would just nest nicely (like “new” would be menu point 3, and “Group” would be 3.1, etc. but no…)

Thanks!