how to activate the guns and turret simple change different camera, the 20mm will automatically activate the 20mm group and along with the turret(no group activation needed on the turret)

Turret can be control in camera each

20mm will only group activation on camera each.

(This is is just a fictional not a real story) the Lore:
In 1932 Philippines need a bomber planes cause the other allied bombers are well made and the budget of the Philippines military is quite low so they built a prototypes from scraps for much cheaper to build the first frame of the bomber and the designers still not convinced if this is the best design yet, 4 years had pass in 1936 the Philippines military finally have a funding to build the proper frame of the bomber and the money to build its prop engines in April, 9, 1936 the prototype takes it first flight without crashing and to much surprised the plane is so maneuvable it can do a fast maneuver of a fighter plane the Philippine air force decided to re-class the bomber to fighter bomber because they don't have a fighter yet in the Philippines air force so in the cockpit they added three seat for 2 pilots on the side for bombing run and 1 seat in the middle for close combat and so they continue to change and test the plane and finally added side gunners, top gunners, and back gunners and after it finalized the plane the designers name it the "PB-1" it stands for
"Philippine Bomber-1"
now in January, 12, 1938 the PB-1 is finally entered service in the Philippines air force only 100 were build.
After it entered service the training for this plane of crew as gunners they train the gunners how to aim while the plane is maneuvering so in case theirs enemies everywhere while the plane is focusing in 1 on 1 with enemy fighters.
In the outbreak of world war 2 imperial japan attack Philippines with its ships and planes the Philippines air force immediately send the all PB-1 to defend its country and after the battle they able to hold against the relentless attack of the empire of japan and destroying zeros and ships along the way not long after they won on the first battle thanks to the PB-1 but for now the empire of japan will do a counter attack against the fighter bomber.