defeat trigger

defeat trigger

i have 5 heroes and there also some units around the map as spectators!!

i want that if all heroes die you loose

ive tried it with integer condition:
player1 units + player 2 units + player3 units + etc. equal or less than 0

action: defeat all players

but that doesnt work :/
any1 have another idea that works??

thx in advance

Have a variable, give it the number of heroes which there is, each time a hero dies estract 1 number from the variable and run a trigger where you check if the variable is = 0 or less.