To replace a string line with a new string after certain line

Question

original file containing

;group 1
-epackage .......

;group2
-epackage .......

After replaced, it should looks like this

;group 1
-epackage .......

;group2
;-epackage

Basically what I want is to comment out the second -epackage

I tried this following code

@echo off setlocal EnableDelayedExpansion

set "search=;group2" set "nextLine=;-epackage"

rem Get the line number of the search line for /F "delims=:" %%a in ('findstr /N /C:"%search%" Load_all.txt') do set /A "numLines=%%a-1"

rem Open a code block to read-input-file/create-output-file

< Load_all.txt (

rem Read the first line set /P "line="

rem Copy numLines-1 lines for /L %%i in (1,1,%numLines%) do set /P "line=!line!" & echo/

rem Replace the next line echo %nextLine%

rem Copy the rest of lines findstr "^"

) > output.txt

rem Replace input file with created output file move /Y output.txt Load_all.txt > NUL

However, the output I got is below

;group 1
-epackage .......

;-epackage
-epackage

Which is not what I want....

Any idea to do the job?