You can do it that way:
Give each unit an individual name (like: w1, w2, etc.).
Now in your init.sqs you could place the following two lines:
PlayerList = []
"if (alive _x) then {PlayerList = PlayerList + [_x]}" foreach [w1,w2,w3,w4,w5,w6,w7,w8,w9,w10,w11,w12]
P.S: this method will not make a difference between AI or player
controlled units - it just fills the array PlayerList with all alive units
from given array: [w1,w2,w3,w4,w5,w6,w7,w8,w9,w10,w11,w12]
In the array you should type each unit's name, which you would
like to be present in PlayerList.
hope this helps
~S~ CD