Here's how I would do it.
Have a computer player in control of 6 death counts, one for each human player, called PlayerXBounty where X is the player's number. Each death count corresponds to one player's kill count or score (depending on how you want to do it), minus the number of heroes he has killed (unless you want those to factor into the bounty too). Each player's kill count will be periodically loaded into the bounty. You'll also have a separate death count for the Computer, which I'll call the "Placeholder" DC.
When you've detected that one player has killed another, then send both players into a "transaction" mode. Prevent anyone else from accessing the computer's Placeholder DC at that moment. Transfer the bounty to Placeholder, then from Placeholder to the killing player's Reward death count. Here's the triggers I would use for all that:
Collapse Box
# of copies per player:
one for every other human player, so 30 total.
O:
All human players
C:
Current player has suffered exactly 6 "KilledPlayer" (means he just killed Player 6's hero)
Current Player has suffered exactly 0 "Transaction".
Player 6 has suffered exactly 0 "Transaction".
Computer has suffered exactly 0 of "Status:Counting".
A:
Set Deaths: Set "Transaction" to 1 (receiver) for current player.
Set Deaths: Set "Transaction" to 2 (giver) for Player 6.
Set Deaths: Set "KilledPlayer" to 0 for Current player.
Set Deaths: Set "Status:Counting" to 1 for Computer.
Preserve Trigger.
# of copies per player:
one, so 6 total.
O:
Player X [change for each human player]
C:
Current player has suffered exactly 2 "Transaction".
Computer has suffered at least 1 of "PlayerXBounty".
Computer has suffered exactly 1 of "Status:Counting".
A:
Set Deaths: Add 1 to "Placeholder" for Computer.
Set Deaths: Subtract 1 from "Player6Bounty" for Computer.
Preserve trigger.
[Have one of these triggers for 16 bounty, one for 8, one for 4, and one for 2, and keep them in descending order. It'll transfer a lot quicker that way, especially if you're using hyper triggers. You can have 32, 64, etc, too. The more there are, the faster the transfer will happen. Just make sure the higher numbers come first.]
# of copies per player:
one, so 6 total.
O:
Player X [change for each human player]
C:
Current player has suffered exactly 2 "Transaction".
Computer has suffered exactly 0 of "PlayerXBounty".
A:
Set Deaths: Set to 0 for "Transaction" for Current Player.
Set Deaths: Set to 2 for "Status:Counting" for Computer.
Preserve trigger.
# of copies per player:
one, so 6 total.
O:
All human players
C:
Current Player has suffered exactly 1 "Transaction".
Computer has suffered exactly 2 of "Status:Counting".
Computer has suffered at least 1 of "Placeholder".
A:
Set Deaths: Add 1 to "Reward" for Current player.
Set Deaths: Subtract 1 from "Placeholder" for Computer.
Preserve trigger.
# of copies per player:
one, so 6 total.
O:
All human players
C:
Current Player has suffered exactly 1 "Transaction".
Computer has suffered exactly 2 of "Status:Counting".
Computer has suffered exactly 0 of "Placeholder".
A:
Set Deaths: Set to 0 for "Status:Counting" for Computer.
Set Deaths: Set to 0 for "Transaction" for Current player.
Preserve trigger.
. . Total triggers: 54
As for detecting a kill... there's really no failsafe way to detect WHOSE hero a player has killed. The best you can do is guess that when Player 1 kills a Templar and Player 2 loses a Templar at the same time, Player 1 killed Player 2's Templar... which is what you were doing in your trigger. The only problem with your trigger is that you subtracted a kill. That's impossible. You can subtract kill SCORE amounts, but you can't subtract the kill COUNT for a unit. One thing you COULD do, though, is something like this:
Collapse Box
# of copies per player:
one, so 6 total.
O:
All human players
C:
Current player has killed 5 templars.
Current player has suffered at most 4 deaths of "HeroKills".
Current player has suffered exactly 0 "KilledPlayer".
A:
Set deaths: Add 1 for "HeroKills" for Current player.
Set deaths: Set to 7 for "KilledPlayer" for Current player.
Preserve trigger.
# of copies per player:
one per every other human player, so 30 total.
O:
All human players.
C:
Current player has suffered exactly 7 deaths of "KilledPlayer".
Player 6 has suffered exactly 1 deaths of templar.
A:
Set deaths: Set to 6 for "KilledPlayer" for Current player.
Set deaths: Set to 0 for templar for Player 6.
Preserve trigger.
. . Total triggers: 36
Alright, let me know if you have any questions. I triple-checked all the triggers but I might have made a typo. It's late.
Color coding:
one of these per player. no changes required.one of these per player. changes required for each player.5 of these per player. changes required for each player.
None.