This is a Group that will spawn a flight of 7 B-25 bombers at 2000 meters and a cover flight of 4 P-51 fighters at 2500 meters upon entry of the Complex Trigger by a selected aircraft.  It includes the first waypoint for each flight.

You will need to ensure that the 'On Object Entered' is appropriate.  I have just used a single country, in this case Germany.  Any German Coalition plane will trigger the flights.
You can also change the plane types in the Properties of each plane.

Enjoy!

Arthur
aka Beebop