From a script, spawn the standard Armored, Mechanized, Motorized_MTP and Infantry east groups at different positions on roads in flat areas about 2 km away from the nearest enemy. Execute “moveInCargo” for each non-crew unit of the mechanized/motorized groups, so the problem should not be waiting for them to load. Add the same waypoint position (move, safe, yellow) for all groups. I am creating the groups with one minute between them, but I have also seen the problem with a five minute interval. I am also spawning 10+ manned vehicles and joining them to the player’s group. When the mission starts I manually send the vehicles of the player’s group to individual positions which they reach without problems. Moving these vehicles makes it more likely that the east groups fail to move. (I have also seen all east groups successfully reach the waypoint if I do not move the vehicles of the player’s group). The east groups are spawned at the north, west and south markers. The waypoint is at the east marker.
Remember to manually order each the vehicles of the player's group to move to an individual position.