<rockstarname> is whatever you put in name field of unit.
Add this to the end of init.sqf:
sleep 1;
if(side player == east) then {rockstarname execVM "tracker.sqf"};
if(isServer && isDedicated) exitWith {};
private ["_unit","_marker"];
_unit = _this;
_marker = createMarkerLocal [format ["%1marker", _unit], getPos _unit];
_marker setMarkerTypeLocal "mil_unknown";
_marker setMarkerColorLocal "ColorBlack";
_marker setMarkerTextLocal "Last Known Pos";
while {alive _unit} do {
_marker setMarkerPosLocal (getPos _unit);
sleep 300; //5 minutes
};
In your tasks code, you can use:
<marker name='rockstarnamemarker'>rockstarname</marker>