Here is the bpstart_notify script for multiple streams that I use
timeout /t %STREAM_NUMBER%
if exist c:\temp\wget_script_running.lock (goto waiting)
echo "" > c:\temp\wget_script_running.lock
<< wget_script command stuff>>
set RETURN=%errorlevel%
del /f c:\temp\wget_script_running.lock
if %RETURN% NEQ 0 (
echo 1 > %6
)
:waiting
if EXIST c:\temp\wget_script_running.lock (
timeout /t 1
goto waiting
)