Considering :
1- That the Diplomacy Chart has different starting positions for all Major Powers, both Axis (Germany, Japan, Italy) and Allies (USA, UK, France), and the USSR.
2- That rule 2.3 of the Expansion states :
" If the player’s roll is successful, the player moves his roundel one position and moves one roundel from any other Major Power from another Alliance down one."
It seems pretty clear that each Major Power is completely independent and that there may be multiple members of an alliance attempting to influence the same country at one time.
So only the nations matter.