A. Unfortunately no, one is your own user startup
It is possible to hide one or both of the startup folders by setting the hidden attribute on the folder:
attrib +h %system root%\Profiles\
A trick has been found to remove one of the startup menus by copying the All Users Startup group over the Administrator Startup group which then deletes the All Users startup group.
To be precise you cannot delete either of the two Startup groups, the settings for both must exist, and the paths for both must exist.
However the Startup group setting is independent of the Start Menu setting. The problem is the Microsoft defaults to putting the Startup group nested inside the Start Menu.
Change the Startup group path in the registry (key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders) to something like:
You can leave the Start Menu path as:
Any shortcuts existing in the Startup group will still get launched even though you do not see them in the StartMenu.