From what I am seeing on the territory and power of each force, this seems to be around befire the Chi Bi battle. So, I think there should be a 12 vs 12 showdown between the top 6 members of shu and wu against the top 12 of wei.

The period that everyone is playing in is after The Battle of Chi Bi.

Valor.Redgrave wrote:

The period that everyone is playing in is after The Battle of Chi Bi.

What he said, Wu and Shu aren't technically allied anymore though they do work together at later points in time but generally it's every man for themselves though Wei did at the time still have a large amount of power or that's what I thought.