I have personally never attempted to touch this file so I can't say for certain.
You could do a simple batch script with a series of echo's with a redirect and append (>>) that point to the HOSTS file.
Or, you could try creating your new HOSTS file on your own PC. Make all the necessary changes required. Then archive with something like WinRAR or Winzip. Then create a package that would unarchive the file into the appropriate directory on the target machine.
The reason for the archive is that it should keep all the necessary permissions and ownership's associated with the HOSTS file.
We used this technique to push local group policies to our hosts because we do not have Active Directory.
You can even copy just the unrar.exe to the client machine and use a commandline command to unrar it. This will unrar and overwrite if the file exists already. Test it though :D
- unrar.exe x -inul -y <source file containing your new HOSTS file> <destination where you want to unrar>
Not sure this is the best way but this is probably how I would go about doing it if I had to.
Cheers