Diplomacy System

Yesterday I played Rise Of Legends and I liked the Diplomacy-System.
I asked myself, if its possible to realise this for WC3

MY IDEA:

You can select the Diplomacy-Ability (Spellbook) in your main building

There is a icon for every player (also Spellbook)

It contains a Ability to declare this player war or a alliance
War: both players get enemies, both get a message
Alliance: both players get allied, both had to accept

And the Diplomacy-Ability also contains a Icon to show all your Friends/Enemies

are nested spellbooks possible?
i dont believe so ...dunno..

Absolutely. Check my submission for Spell Session 13; the Archmage unit has most of the game's hero abilities. All the neutral hero abilities are in nested spellbooks.

Could it be possible, that one Player is in different teams?