You can make a Script like this:
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_FoeArray = _this select 0; the array of enemy's [e1,e2,,..... and soo on
_group = _this select 1; the Men you is to kill the guys in _FoeArray
_gunners = units _group
_amount = count _gunners
_i = 0
_g = 0
_u = 0
#loop
? _i >= 11 : goto "CheckReady"
_gunners select _i dotarget _FoeArray select _i
_i = _i + 1
~0.1
goto "loop"
#CheckReady
? _g = _amount : _g = 0
? _u = _amount : goto "Fire"
? unitready _gunners select _g : _u = _u + 1
_g = _g + 1
~0.1
goto "CheckReady"
#fire
"_x dofire objnull" foreach _gunners
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Enjoy