I have a better idea...
How about you have a MoM forum which all 3 countries have access to. This way, it is far easier to arrange when a country will have 100+ flying in one sector and the other countries will know ahead of time to avoid it to prevent ruining your massive mission.
Also, all the countries can take bases in a clockwise or counter-clockwise direction and never have to see any opposition, what so ever. Whoever takes the most bases in the shorter period of time, wins!