This is what Ched spent many hours working on. We should not let all his
hard work and efforts go in vain.
In answer to your question- no, unless there is one and I missed an update for the script syntax file. I did a search of the one I have from 13 Dec 2012 (Issue 5.1)and did not find anything regarding "AI hit". I did find the following:
3.1.1.33 SHOTBYAMMO=Name
Description: Is true when the entity has been shot by the ammo named.
Range: X = Ammo name.
Example: :shotbyammo=Nato556:state=1
The above may be of use to you- you might be able to use that condition to work around your result.
There's no problem that can't be solved without applying a little scripting.