http://www.xalmat.com/eqsummoners.co...hain-pets.html
This is a link that describes how to chain pet. Its a very basic idea of the process, but none of it is possible with the way pets are now. The aggro from the low level spell, the regening of mana because you cant sit. Besides the fact your new pet cant get aggro off of you.
As far as I can tell, this is dated 2005. So unless pets had no aggro before that point (which I know its been this way for a very long time) and then SOE patched the aggro problem out. I dont think its working as intended.