[Paracelsus]

When saying "all kill", it is better not stay between the mares...
I used the training method above a long time ago. But, I ended up killing myself and mare died. This is owing to my computer reboot after Ms patching and unstable network connection.
I re-design my house to add the door between the mare to block the line of sign. Something like:

wall
Mare (chest) [door] (chest) Mare
wall

I don't need to say "all kill", "all stop". What I need to do is let them kill each other at the beginning. Then, open and close the door. Once they are in sight, they start casting. Once the door closes, they just can't fire.

In case my network connection loss, the door cannot be opened since the macro not longer running. They just keep hating each other, but no harm. :-)

That is Paracelsus's Door for mare training. ^^