[Georgio]

Код:

@echo off
setlocal enabledelayedexpansion
for %%i in (
 @mail
 @bk
 @list
 @inbox
 @yandex
 @ya.
 @narod
 ) do (
 set /a n+=1
 if !n! leq 4 (
  set "file=Mail.txt"
  ) else (
  set "file=Yandex.txt"
  )
 findstr /lic:"%%i" "1.txt">>"!file!"
 )
endlocal
exit /b