_center = getmarkerpos "markername";
_range = getMarkerSize "markername";
_start = [(_center select 0) + random (_range select 0) - random (_range select 0),(_center select 1) + random (_range select 1) - random (_range select 1),0];
while {player distance _start < 500} do {_start = [(_center select 0) + random (_range select 0) - random (_range select 0),(_center select 1) + random (_range select 1) - random (_range select 1),0];};
_group = [_start, EAST, ["TK_INS_Soldier_EP1"],[],[],[0.7,0.9]] call BIS_fnc_spawnGroup;
With that while loop it also checks that the unit dosent spawn near player.