Can you stack more than 2 Warlock DoT spells like this?

[blocklandmac]

At higher levels, (level 40+) Warlocks get AoE damage over time spells. They have a front range radius of 7 meters.

Anyway... I've been hearing that you can only cast two of these on any monster. However, is it possible to cast two of them on a monster, have it affect other monsters nearby, select another monster, then cast two different ones to have four in total on all of the monsters?

I'm just curious.


Thanks. =)