Can this effect be used by multiple characters that can use Poison in a turn or is it limited to one character?

For example, if I have three characters that each have Poison, can I move them all adjacent to a single opposing character and deal that character three clicks of damage using Poison in a single turn?

The effect works or all and any characters that can use poison as long as the card is in effect, your and your's opponents.

Wow, that is powerful! Thanks.