Herald of Anafenza

I have a doubt about the second ability of Herald of Anafenza.
It says : Whenever you activate Herald of Anafenza's outlast ability, put a 1/1 white Warrior creature token onto the battlefield
It is referred to the same card instance or it will be activated also if another card instance use outlast ability?
I mean i have 3 Herald of Anafenza onto battlefield, i use Outlast on the first one and it takes the +1 / +1 counter, now about the tokens will produce the token only the card i have activated outlast or all 3 Herald of Anafenza ???
It says : Whenever you activate Herald of Anafenza's outlast ability, put a 1/1 white Warrior creature token onto the battlefield
It is referred to the same card instance or it will be activated also if another card instance use outlast ability?
I mean i have 3 Herald of Anafenza onto battlefield, i use Outlast on the first one and it takes the +1 / +1 counter, now about the tokens will produce the token only the card i have activated outlast or all 3 Herald of Anafenza ???