Does attacking a zombie in the nether cause the zombie pigmen to become hostile?

I created a portal in the nether and it led into an abandoned mine. I explored the abandoned mine for a while before re-entering the Nether where I found a number of skeletons and zombies had wandered in. One of the zombies attacked me, so I attacked back and I think the surrounding zombie pigmen became hostile (I died before I knew what was going on).

Can someone confirm that this actually does happen? Is this a bug or is it intentional? (ie the zombie pigmen see their overworld counterparts as kindred spirits or something)

I was on snapshot 14w06b

Let's do this with SCIENCE

I'm going to test this by bringing a zombie to the nether and punching him around some Pigmen. If this hypothesis was true, then the Zombie Pigmen should kill me instantly because that's what they do.

I did exactly this, making extra sure to not hit the Pigmen, and reproduced exactly this result. It seems that Zombie Pigmen still take care of their Zombie brothers. I'm not sure if this is intentional or not, but I doubt it's a bug, since Zombies and Zombie Pigmen are entirely separate entities.

Pigmen are deadly, and some of them probably picked up your stuff. Good luck.