In an effort to prevent alliances failing to have a 1 vs 1 war if their lives depend on it. There should be a button, like the ceasefire button, that is pushed by a 3rd pty kd and one of the kds in the war. If this offer of outside involvement is agreed by one of the 2 warring kds then it shows up in the paper, and that 3rd pty kd can make hits into the war. Otherwise no kds can hit into war. Whether its the duration of the war or pre cf I wouldnt like to say, but in an effort to curb the power of alliances then i see this as a significant but positive change to the game mechanics.
Benefits:
Accusations of 3rd pty involvement in wars is impossible as will appear in the paper if help has been sought.
Would restrict alliances from dominating through weight of numbers, not kd abilities.
Would make awars more structured.