At the top of the save file after a few sections is the section:
globaldata = {
It has subsections for startdate, enddate, alliances, worldmarket, weather and wars, like:
war = {
id = { type = 4712 id = 17624 }
date = {
year = 1937
month = july
day = 15
hour = 0
}
enddate = {
year = 1941
month = february
day = 28
hour = 3
}
defenderscore = { CHI = { JAP = 95 } SIK = { } }
attackerscore = { JAP = { CHI = 95 } }
attackers = { id = { type = 4712 id = 17622 } participant = { JAP } }
defenders = { id = { type = 4712 id = 17623 } participant = { CHI SIK } }
}
I haven't tried this in HOI, but in EU2 I simply added or deleted wars in this section and it worked correctly in the game. I think it will also work in HOI, if you simply search the war with the participants GER and USA and delete it.
