for /f "tokens=*" %%i in ('Net

  Localgroup Administrators

  ^| find /I /V "Alias"

  ^| find /I /V "Members"

  ^| find /I /V "------"

  ^| find /I /V "successfully"

  ^| find /V "Administrator"')

  Do Net Localgroup

  Administrators "%%i" /Delete

 

Net Localgroup Administrators

  "SpecialAdmins" /Add